U.S. patent number 8,522,551 [Application Number 12/997,049] was granted by the patent office on 2013-09-03 for apparatus for determining an abnormality of a control valve of an internal combustion engine.
This patent grant is currently assigned to Toyota Jidosha Kabushiki Kaisha. The grantee listed for this patent is Yoshihisa Hirosawa, Taku Ibuki, Tetsuji Tomita. Invention is credited to Yoshihisa Hirosawa, Taku Ibuki, Tetsuji Tomita.
United States Patent |
8,522,551 |
Tomita , et al. |
September 3, 2013 |
Apparatus for determining an abnormality of a control valve of an
internal combustion engine
Abstract
An apparatus for determining an abnormality of a control valve
is applied to an internal combustion engine having a first
supercharger, a second supercharger, a first control valve, and a
second control valve. The apparatus includes an electronic control
unit to obtain two supercharging-pressure-corresponding-values
before and after an opening degree of the first control valve is
changed during a period in which the engine is operated in a
specific operating state under which the first supercharger
supercharges the engine more efficiently than the second
supercharger, and to determine whether or not the second control
valve is abnormal based on the two values with respect to the
change of the opening degree of the first control valve.
Inventors: |
Tomita; Tetsuji (Susono,
JP), Ibuki; Taku (Gotenba, JP), Hirosawa;
Yoshihisa (Kariya, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Tomita; Tetsuji
Ibuki; Taku
Hirosawa; Yoshihisa |
Susono
Gotenba
Kariya |
N/A
N/A
N/A |
JP
JP
JP |
|
|
Assignee: |
Toyota Jidosha Kabushiki Kaisha
(Aichi, JP)
|
Family
ID: |
43449071 |
Appl.
No.: |
12/997,049 |
Filed: |
July 16, 2009 |
PCT
Filed: |
July 16, 2009 |
PCT No.: |
PCT/JP2009/063236 |
371(c)(1),(2),(4) Date: |
December 09, 2010 |
PCT
Pub. No.: |
WO2011/007456 |
PCT
Pub. Date: |
January 20, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20110167816 A1 |
Jul 14, 2011 |
|
Current U.S.
Class: |
60/612; 60/611;
123/562 |
Current CPC
Class: |
F02B
37/16 (20130101); F02B 77/082 (20130101); F02B
37/18 (20130101); F02B 37/004 (20130101); F02B
39/16 (20130101); F02B 37/013 (20130101); F02D
41/221 (20130101); Y02T 10/12 (20130101); Y02T
10/144 (20130101); Y02T 10/40 (20130101); F02D
2200/0406 (20130101) |
Current International
Class: |
F02B
37/013 (20060101); F02B 33/44 (20060101); F02B
33/00 (20060101) |
Field of
Search: |
;60/612,611,602
;123/562 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1 678 415 |
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Jul 2006 |
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EP |
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320986 D |
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Oct 1929 |
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GB |
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02-063046 |
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Mar 1990 |
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JP |
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02-078734 |
|
Mar 1990 |
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JP |
|
03-106133 |
|
May 1991 |
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JP |
|
04017723 |
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Jan 1992 |
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JP |
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2002-276382 |
|
Sep 2002 |
|
JP |
|
2005-226501 |
|
Aug 2005 |
|
JP |
|
2007-505257 |
|
Mar 2007 |
|
JP |
|
2008297994 |
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Dec 2008 |
|
JP |
|
Other References
Japanese Office Action dated Dec. 21, 2011, issued in corresponding
Japanese Patent Application No. 2010-535926. cited by applicant
.
Translation of International Preliminary Report on Patentability
for corresponding International Patent Application No.
PCT/JP2009/063236 issued on Feb. 7, 2012. cited by applicant .
Chinese Office Action dated Sep. 19, 2012, issued in Chinese
Application No. 200980101101.5. cited by applicant.
|
Primary Examiner: Denion; Thomas
Assistant Examiner: Nguyen; Ngoc T
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
The invention claimed is:
1. An apparatus for determining an abnormality of a control valve,
the apparatus being applied to an internal combustion engine
having: a first supercharger comprising a first turbine disposed in
an exhaust gas passage of the engine and a first compressor
disposed in an intake air passage of the engine and driven by the
first turbine which is driven by an exhaust gas flowing in the
exhaust gas passage; a second supercharger comprising a second
turbine disposed in the exhaust gas passage at a downstream side of
the first turbine and a second compressor disposed in the intake
air passage at an upstream side of the first compressor and driven
by the second turbine which is driven by the exhaust gas; a first
passage section whose one end is connected to the exhaust gas
passage at an upstream side of the first turbine and whose the
other end is connected to the exhaust gas passage between the first
turbine and the second turbine; a first control valve, disposed in
the first passage section, for varying a flow passage area of the
first passage section depending on an opening degree of the first
control valve; a second passage section whose one end is connected
to the intake air passage between the first compressor and the
second compressor and whose the other end is connected to the
intake air passage at a downstream side of the first compressor,
and a second control valve, disposed in the second passage section,
for varying a flow passage area of the second passage section
depending on an opening degree of the second control valve, the
engine is configured in such a manner that the first control valve
and the second control valve are operated in such a manner that the
first supercharger superchargers the engine more efficiently than
the second supercharger when the engine is operated in a
predetermined operating area, the apparatus for determining an
abnormality of a control valve comprising an electronic control
unit having control logic configured to cause the electronic
control unit to perform the following: first operation to obtain a
supercharging-pressure-corresponding-value which becomes larger as
a pressure of air in the intake air passage at the downstream side
of the first compressor becomes larger; second operation to obtain,
as a first value, the obtained
supercharging-pressure-corresponding-value; operate the first
control valve, at a first timing after the timing at which the
first value is obtained, in such a manner that the opening degree
of the first control valve coincides with a second opening degree
different from a first opening degree which is an opening degree of
the first control valve at a timing when the first value is
obtained; and obtain, as a second value, the obtained
supercharging-pressure-corresponding-value at a second timing at
which a predetermined time has elapsed from the first timing,
during a period in which an abnormality determining condition
including at least a condition that the engine is operated in the
predetermined area is satisfied, and third operation to determine
that the second control valve is abnormal, if the second opening
degree is larger than the first opening degree and the second value
is larger than the first value, or if the second opening degree is
smaller than the first opening degree and the second value is
smaller than the first value.
2. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the electronic control unit is
configured to obtain a supercharging pressure which is a pressure
of air in the intake air passage at the downstream side of the
first compressor as the supercharging-pressure
corresponding-value.
3. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the electronic control is configured
to obtain an amount of new air introduced into the engine as the
supercharging-pressure-corresponding-value.
4. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the electronic control is configured
to determine that the first control valve is abnormal if an
absolute value of a difference between the second value and the
first value is smaller than a first control valve abnormality
determination threshold value.
5. The apparatus for determining an abnormality of a control valve
according to claim 4, wherein the electronic control is configured
to infer that the second control valve is normal if the electronic
control unit determines that the first control valve is
abnormal.
6. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the second control valve is operated
to close the second passage section when the engine is operated in
the predetermined operating area.
7. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the second control valve comprises a
valve, a valve seat portion against which the valve rests, and a
spring for biasing the valve toward the valve seat portion, and the
second control valve is configured in such a manner that the valve
is moved to a first position at which the valve rests against the
valve seat portion by an biasing force generated by the spring so
as to close the second passage section when a pressure of air in
the second passage section at an upstream side of the second
control valve is not larger than a pressure of air in the second
passage section at an downstream side of the second control valve
by a predetermined pressure or more, and in such a manner that the
valve is moved to a second position different from the first
position against the biasing force generated by the spring so as to
increase the flow passage area of the second passage section when
the pressure of air in the second passage section at the upstream
side of the second control valve is larger than the pressure of air
in the second passage section at the downstream side of the second
control valve by the predetermined pressure or more.
8. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the first control valve includes a
valve actuator varying the opening degree of the first control
valve to change the flow passage area of the first passage section
in response to an instruction signal, and the electronic control
unit is configured to change the opening degree of the first
control valve by sending the instruction signal to the valve
actuator.
9. The apparatus for determining an abnormality of a control valve
according to claim 1, wherein the abnormality determining condition
is a condition that is satisfied when at least a requirement that
the engine is operated in a deceleration state in which a torque
required for the engine is smaller than or equal to a predetermined
torque is met.
Description
TECHNICAL FIELD
The present invention relates to an apparatus for determining an
abnormality of a control valve, applied to an internal combustion
engine having a plurality of superchargers (turbochargers) and a
plurality of control valves for controlling the plurality of
superchargers.
BACKGROUND ART
A conventionally known supercharger (exhaust gas turbine type
supercharger) comprises a turbine which is disposed in an exhaust
gas passage of an internal combustion engine and is driven by
energy of an exhaust gas, and a compressor which is disposed in an
intake air passage of the engine and is driven by the driven
turbine. Accordingly, an air introduced into the compressor is
compressed by the compressor, and thereafter the air is discharged
toward combustion chambers. That is, a supercharging is
performed.
It is well known that the supercharger can substantially compress
an air introduced into the compressor, when a flow rate of the air
is within a range from a predetermined surge flow rate to a
predetermined choked flow rate. Generally, both of the surge flow
rate and the choked flow rate increase as a capacity of the
supercharger becomes greater. Accordingly, when only one
supercharger having a relatively small capacity is used to perform
the supercharging, the flow rate of the air introduced into the
compressor reaches the choked flow rate under a high load operating
condition of the engine, and therefore the supercharging can not be
performed. On the other hand, when only one supercharger having a
relatively large capacity is used to perform the supercharging, the
flow rate of the air introduced into the compressor becomes smaller
than the surge flow rate under a low load operating condition of
the engine, and therefore the supercharging can not be performed.
It is therefore understood that an operating area (load area) in
which an internal combustion engine having a single supercharger
can be appropriately supercharged is small compared to a whole
operating area of the engine.
In view of the above, one of conventional internal combustion
engines comprises: a first supercharger having a small capacity; a
second supercharger having a large capacity and being connected in
series with the first supercharger; a plurality of bypass passages
for adjusting an air flow rate or an exhaust gas flow rate supplied
to the first supercharger and the second supercharger, and a
plurality of control valves disposed in the bypass passages. In
this internal combustion engine, both the first supercharger and
the second supercharger are appropriately used depending on the
operating condition of the engine. This allows the operating area
(load area) in which the engine is appropriately supercharged to be
expanded.
In the conventional internal combustion engine described above, for
example, a control valve (exhaust gas changeover valve) is disposed
in a bypass passage for adjusting an exhaust gas flow rate supplied
to the turbine of the first supercharger. This exhaust gas
changeover valve is controlled by a control apparatus so as to be
closed when the load of the engine is low and so as to be opened
when the load of the engine is high. This allows the first
supercharger having the small capacity to operate mainly when the
engine is operated under the low load condition. In the meantime,
this allows the second supercharger having the large capacity to
operate mainly when the engine is operated under the high load
condition. As a result, the engine is appropriately supercharged in
a greater operating area, compared to an area where the engine
having a single supercharger can be appropriately supercharged.
The control apparatus which the conventional internal combustion
engine comprises determines whether or not the exhaust gas
changeover valve operates properly/normally in order to retain a
state where the engine is appropriately supercharged as described
above. Specifically, the control apparatus stores/memorizes "a
maximum value of the supercharging pressure when the exhaust gas
changeover valve operates normally", the maximum value of the
supercharging pressure being obtained by experiments performed in
advance. Further, the control apparatus is configured in such a
manner that it determines that the exhaust gas changeover valve is
abnormal/anomalous when "an actual supercharging pressure" becomes
larger than "the stored maximum value of the supercharging
pressure" (see, for example, Japanese Examined Utility Model No.
Hei 3-106133).
DISCLOSURE OF THE INVENTION
In the meantime, in order to retain such a condition where the
engine is appropriately supercharged as described above, it is
preferable for the control apparatus to determine not only whether
or not the exhaust gas changeover valve operates properly, but also
whether or not another control valve other than the exhaust gas
changeover valve operates properly. More specifically, it is
preferable for the control apparatus to further determine whether
or not "a control valve (intake air changeover valve) disposed in a
bypass passage for adjusting a flow rate of an air supplied to the
compressor of the first supercharger" operates properly. However,
the utility model does not disclose how to determine whether or not
the intake air changeover valve operates normally at all.
The present invention is made to solve the problem described above.
That is, one of objects of the present invention is to provide an
apparatus for determining an abnormality of a control valve,
applied to "an internal combustion engine having a plurality of
superchargers, a plurality of bypass passages, and a plurality of
control valves including the intake air changeover valve", which
can determine whether or not the intake air changeover valve
operates normally.
The apparatus for determining an abnormality of a control valve of
an internal combustion engine which solves the problem described
above is applied the internal combustion engine comprising: a first
supercharger (turbocharger); a second supercharger (turbocharger);
a first passage section; a first control valve corresponding to the
exhaust gas changeover valve; a second passage section; and a
second control valve corresponding to the intake air changeover
valve.
The first supercharger comprises a first turbine and a first
compressor.
The first turbine is disposed in an exhaust gas passage.
Accordingly, the first turbine is driven by energy of an exhaust
gas which is introduced into the first turbine. The first
compressor is disposed in an intake air passage of the engine. The
first compressor is configured so as to be driven by the driven
first turbine. Consequently, the first compressor compresses an air
introduced into the first compressor.
The second supercharger comprises a second turbine and a second
compressor.
The second turbine is disposed in the exhaust gas passage at a
downstream side of (at a position downstream of) the first turbine.
Accordingly, the second turbine is driven by energy of an exhaust
gas which is introduced into the second turbine. The second
compressor is disposed in the intake air passage at an upstream
side of (at a position upstream of) the first compressor. The
second compressor is configured so as to be driven by the driven
second turbine. Consequently, the second compressor compresses an
air introduced into the second compressor. That is, the first
supercharger and the supercharger are connected in series with each
other.
The first passage section is a passage, whose one end is connected
to the exhaust gas passage at an upstream side of the first turbine
and whose the other end is connected to the exhaust gas passage
between the first turbine and the second turbine. That is, the
first passage section constitutes a passage which bypasses the
first turbine.
The first control valve is disposed in the first passage section.
The first control valve is configured so as to change a passage
area of the first passage section depending on an opening degree of
the first control valve. Accordingly, the first control valve
changes a ratio between "a magnitude of energy of the exhaust gas
introduced into the first turbine" and "a magnitude of energy of
the exhaust gas introduced into the second turbine".
The second passage section is a passage, whose one end is connected
to the intake air passage between the first compressor and the
second compressor, and whose the other end is connected to the
intake air passage at a downstream side of the first compressor.
That is, the second passage section constitutes a passage which
bypasses the first compressor.
The second control valve is disposed in the second passage section.
The second control valve is configured so as to change a passage
area of the second passage section depending on an opening degree
of the second control valve. Accordingly, the second control valve
changes a ratio between "an amount of the air introduced into the
first compressor" and "an amount of an air passing through the
second passage section".
Further, the internal combustion engine is configured in such a
manner that the first control valve and the second control valve
are operated so that "at least the first compressor compresses the
air introduced into the first compressor and discharges the
compressed air (that is, the first compressor supercharges the
engine)", when the engine is operated in "a predetermined operating
area".
"The predetermined operating area" is an area which substantially
coincides with an operating area in which "the first supercharger",
among the first supercharger and the second supercharger, mainly
supercharges the engine. The expression of "mainly supercharges"
means that one of the first supercharger and the second
supercharger supercharges the engine more efficiently than the
other one of the superchargers. That is, "the first supercharger
mainly supercharges the engine" means that "both the first
supercharger and the second supercharger supercharge the engine,
and the first supercharger supercharges the engine more efficiently
than the second supercharger", or "only the first supercharger,
among the first supercharger and the second supercharger,
substantially supercharges the engine".
In addition, the apparatus for determining an abnormality of a
control valve of the present invention, which is applied to the
internal combustion engine described above, comprises
supercharging-pressure-corresponding-value-obtaining-means and
control valve abnormality determination means.
More specifically, the
supercharging-pressure-corresponding-value-obtaining-means is
configured so as to obtain "a
supercharging-pressure-corresponding-value" which becomes larger as
a pressure of an air in the intake air passage at the downstream
side of the first compressor becomes larger.
It should be noted that "the pressure of the air in the intake air
passage at the downstream side of the first compressor" may be a
pressure of an air immediately after passing through the first
compressor. Further, "the pressure of the air in the intake air
passage at the downstream side of the first compressor" may be a
pressure of an air in the intake air passage at a downstream side
of "a pressure loss generation member disposed between the first
compressor and combustion chambers, such as an intercooler and a
throttle valve for a diesel engine". That is, "the pressure of the
air in the intake air passage at the downstream side of the first
compressor" is a pressure varying depending on a change in a
supercharging condition of the first supercharger.
The supercharging-pressure-corresponding-value is not specifically
limited, as long as it is a value which becomes larger as "the
pressure of the air in the intake air passage at the downstream
side of the first compressor" becomes larger. For example, "a
supercharging pressure" which is the pressure of the air in the
intake air passage at the downstream side of the first compressor
may be adopted as the supercharging-pressure-corresponding-value.
Further, for example, "an amount of a new air" which is an amount
of an air introduced into the engine may be adopted as the
supercharging-pressure-corresponding-value.
The control valve abnormality determination means is configured in
such a manner that,
(1) the control valve abnormality determination means obtains, as
"a first value", the obtained
supercharging-pressure-corresponding-value, during a period in
which "an abnormality determining condition" including at least a
condition that the engine is operated in the predetermined area is
satisfied;
(2) the control valve abnormality determination means operates the
first control valve, at a first timing after the timing at which
the first value is obtained, in such a manner that the opening
degree of the first control valve coincides with "a second opening
degree" different from "a first opening degree which is an opening
degree of the first control valve at a timing when the first value
is obtained";
(3) the control valve abnormality determination means obtains, as
"a second value", the obtained
supercharging-pressure-corresponding-value at a second timing at
which a predetermined time has elapsed from the first timing.
Furthermore, the control valve abnormality determination means is
configured in such a manner that,
(4) the control valve abnormality determination means determines
that "the second control valve is abnormal", (a) if the second
opening degree is larger than the first opening degree and the
second value is larger than the first value, or (b) if the second
opening degree is smaller than the first opening degree and the
second value is smaller than the first value.
As described above, in the apparatus for determining an abnormality
of a control valve according to the present invention, the first
control valve is operated during the period in which "the
abnormality determining condition" is satisfied in such a manner
that the opening degree of the first control valve changes from
"the first opening degree" to "the second opening degree".
Thereafter, the supercharging-pressure-corresponding-value when the
opening degree of the first control valve is the first opening
degree (i.e., the first value) is compared with the
supercharging-pressure-corresponding-value when the opening degree
of the first control valve is the second opening degree (i.e., the
second value). Further, "whether or not the second control valve is
abnormal" is determined base on a result of the comparison.
In the present invention, the first opening degree may be larger or
smaller than the second opening degree. Accordingly, a principle
which the control valve abnormality determination means adopts in
order to determine "whether or not the second control valve is
abnormal" will be described hereinafter, for a case where "the
second opening degree is larger than the first opening degree" and
for a case where "the second opening degree is smaller than the
first opening degree", separately.
1. In a case where the second opening degree is larger than the
first opening degree (i.e., a case where the opening degree of the
first control valve is increased).
As described above, the first control valve is disposed in the
first passage section, whose one end is connected to the exhaust
gas passage at the upstream side of the first turbine and whose the
other end is connected to the exhaust gas passage between the first
turbine and the second turbine. Therefore, a flow rate of the
exhaust gas passing through the first passage section increases as
the opening degree of the first control valve increases.
Consequently, the magnitude of the energy supplied to the first
turbine decreases and the magnitude of the energy supplied to the
second turbine increases, as the opening degree of the first
control valve increases.
In the meantime, as described above, as long as the second control
valve is "normal", the second control valve is operated in such a
manner that "at least the first compressor compresses the air
introduced into the first compressor and discharges the compressed
air" when the engine is operated in "the predetermined operating
area".
Accordingly, when the opening degree of the first control valve is
changed from the first opening degree to the second opening degree,
the amount of the exhaust gas passing through the first passage
section increases (i.e., the energy supplied to the first turbine
decreases), and therefore a pressure ratio of the first compressor
(=a pressure of an air at the downstream side of the first
compressor/a pressure of an air at the upstream side of the first
compressor) "decreases", if the second control valve is
"normal".
Further, when the opening degree of the first control valve is
changed from the first opening degree to the second opening degree
as described above, the energy supplied to the second turbine
increases by an amount of the energy corresponding to an increased
amount of the flow rate of the exhaust gas passing through the
first passage section, and therefore a pressure ratio of the second
compressor (=a pressure of an air at the downstream side of the
second compressor/a pressure of an air at the upstream side of the
second compressor) "increases", if the second control valve is
"normal".
In the meantime, "the abnormality determining condition" includes
the condition which is satisfied "when the engine is operated in
the predetermined area". Accordingly, when the engine is operated
in the predetermined area, "the first supercharger" among the first
supercharger and the second supercharger "mainly" supercharges the
engine. Therefore, the pressure ratio of the first compressor is
larger than the pressure ratio of the second compressor, when the
opening degree of the first control valve is at the first opening
degree. Further, when the opening degree of the first control valve
is changed, a change amount in the pressure ratio of the first
compressor is larger than a change amount in the pressure ratio of
the second compressor. Consequently, when the opening degree of the
first control valve is changed (increased in this case) from the
first opening degree to the second opening degree, "a decreasing
amount in the pressure ratio of the first compressor" is larger
than "an increasing amount in the pressure ratio of the second
compressor".
The supercharging pressure is obtained by multiplying "a pressure
(generally, an atmospheric pressure) of an air flowing into the
engine from its outside" by "a product of the pressure ratio of the
first compressor and the pressure ratio of the second compressor
(herein after, the product will be referred to as "total pressure
ratio")". As described above, "the decreasing amount in the
pressure ratio of the first compressor" is larger than "the
increasing amount in the pressure ratio of the second compressor",
when the opening degree of the first control valve is changed from
the first opening degree to the second opening degree. Accordingly,
the total pressure ratio decreases when the opening degree of the
first control valve is changed from the first opening degree to the
second opening degree, and therefore the supercharging pressure
decreases.
To the contrary, if the second control valve is "abnormal", the
first compressor can not compress the air introduced into the first
compressor to discharge the compressed air, even when the engine is
operated in the predetermined operating area. In other words, when
the second control valve is "abnormal", such as when the second
control valve is fully opened, the pressure at the upstream side of
the first compressor is substantially equal to the pressure at the
downstream side of the first compressor.
Accordingly, if the second control valve is "abnormal", the
pressure ratio of the first compressor is substantially "1" when
the opening degree of the first control valve is set at the first
opening degree. In addition, if the second control valve is
"abnormal", the pressure ratio of the first compressor is also
substantially "1" when the opening degree of the first control
valve is set at the second opening degree. That is, if the second
control valve is "abnormal", the pressure ratio of the first
compressor remains unchanged even when the opening degree of the
first control valve is changed from the first opening degree to the
second opening degree.
To the contrary, the second compressor can compress the air
introduced into the second compressor and discharge the compressed
air, even when the second control valve is abnormal. Accordingly,
when the opening degree of the first control valve is changed
(increased in this case) from the first opening degree to the
second opening degree, the pressure ratio of the second compressor
increases.
Therefore, if the second control valve is "abnormal", the total
pressure ratio increases by an amount corresponding to the increase
amount in the pressure ratio of the second compressor, when the
opening degree of the first control valve is changed from the first
opening degree to the second opening degree. As a result, the
supercharging pressure "increases".
As described above, when the opening degree of the first control
valve is changed from the first opening degree to the second
opening degree larger than the first opening degree, the
supercharging pressure "decreases" if the second control valve is
"normal", and the supercharging pressure "increases" if the second
control valve is "abnormal". In view of the above, the control
valve abnormality determination means determines that "the second
control valve is abnormal" when the condition described above
(refer to (4) (a) above) is satisfied.
2. In a case where the second opening degree is smaller than the
first opening degree (i.e., a case where the opening degree of the
first control valve is decreased).
The flow rate of the exhaust gas passing through the first passage
section decreases and the flow rate of the exhaust gas introduced
into the first turbine increases, as the opening degree of the
first control valve decreases. Therefore, the magnitude of the
energy supplied to the first turbine therefore increases and the
magnitude of the energy supplied to the second turbine decreases,
as the opening degree of the first control valve decreases.
Accordingly, when the opening degree of the first control valve is
changed from the first opening degree to the second opening degree,
the energy supplied to the first turbine increases, and therefore
the pressure ratio of the first compressor increases if the second
control valve is "normal". At the same time, the pressure ratio of
the second compressor "decreases".
As described above, when the abnormality determining condition is
satisfied, the pressure ratio of the first compressor is larger
than the pressure ratio of the second compressor. Further, when the
opening degree of the first control valve is changed from the first
opening degree to the second opening degree, an increasing amount
in the pressure ratio of the first compressor is larger than a
decreasing amount in the pressure ratio of the second compressor.
Accordingly, at this time, the total pressure ratio increases. As a
result, the supercharging pressure "increases".
To the contrary, if the second control valve is "abnormal", the
pressure ratio of the first compressor remains unchanged even when
the opening degree of the first control valve is changed, as
described above. In the meantime, the second compressor can
compress the air introduced into the second compressor and
discharge the compressed air, even if the second control valve is
"abnormal". Accordingly, when the opening degree of the first
control valve is changed (decreased in this case) from the first
opening degree to the second opening degree, the pressure ratio of
the second compressor decreases.
Accordingly, if the second control valve is abnormal, the total
pressure ratio decreases by an amount corresponding to the decrease
amount in the pressure ratio of the second compressor, when the
opening degree of the first control valve is changed from the first
opening degree to the second opening degree. As a result, the
supercharging pressure "decreases".
As described above, when the opening degree of the first control
valve is changed from the first opening degree to the second
opening degree smaller than the first opening degree, the
supercharging pressure "increases" if the second control valve is
"normal", and the supercharging pressure "decreases" if the second
control valve is "abnormal". In view of the above, the control
valve abnormality determination means determines that "the second
control valve is abnormal" when the condition described above
(refer to (4) (b) above) is satisfied. These are the principle to
determine the abnormality of the second control valve adopted by
the control valve abnormality determination means.
In the principle described above, "the supercharging pressure" is
used as an indicative parameter to determine whether or not the
second control valve is abnormal. However, the indicative parameter
is not limited to the supercharging pressure. That is, it is
possible to determine whether or not the second control valve is
abnormal based on "an amount which increases as the supercharging
pressure increases (i.e., the
supercharging-pressure-corresponding-value)" as the indicative
parameter in place of "the supercharging pressure", according to
the principle described above.
In this manner, in the internal combustion engine having the
plurality of the superchargers, the plurality of the bypass
passages, and the plurality of the control valves including the
intake air changeover valve, the apparatus for determining an
abnormality of a control valve of the present invention operates
the first control valve forcibly, and can determine whether or not
the second control valve which is the intake air changeover valve
is abnormal based on the result caused by the forcible operation of
the first control valve.
Further, the control apparatus of the present invention can
determine whether or not the second control valve is abnormal
without disposing, in the second control valve, an opening degree
sensor which directly detects the opening degree of the second
control valve. As a result, a cost for manufacturing the engine can
be reduced.
It should be noted that, in the control apparatus of the present
invention, it is not necessary to always monitor both of whether or
not "the second opening degree is larger than the first opening
degree and the second value is larger than the first value" and
whether or not "the second opening degree is smaller than the first
opening degree and the second value is smaller than the first
value". That is, the apparatus may monitor either one of those two
only.
As described above, the
supercharging-pressure-corresponding-value-obtaining-means of the
apparatus for determining an abnormality of a control valve of the
present invention according to the present invention is configured
in such a manner that it obtains, as the
supercharging-pressure-corresponding-value, "the amount which
increases as the supercharging pressure increases".
The supercharging-pressure-corresponding-value-obtaining-means can
be configured in such a manner that it obtains, as the
supercharging-pressure-corresponding-value, "a supercharging
pressure" which is a pressure of an air in the intake air passage
at the downstream side of the first compressor. Further, the
supercharging-pressure-corresponding-value-obtaining-means can be
configured in such a manner that it obtains, as the
supercharging-pressure-corresponding-value, "an amount of a new
air" which is an amount of an air introduced into the engine.
In the apparatus for determining an abnormality of a control valve,
it is preferable that the control valve abnormality determination
means be configured in such a manner that it determines that "the
first control valve is abnormal" when "an absolute value of a
difference between the second value and the first value" is smaller
than a first control valve abnormality determination threshold
value.
As described above, the control valve abnormality determination
means changes the opening degree of "the first control valve" from
the first opening degree to the second opening degree, in order to
determine whether or not "the second control valve" is abnormal. In
the meantime, when a movable portion of "the first control valve"
whose opening degree is to be changed fixed due to, for example, an
adhesion of a solid composition (e.g. a soot, and the like) to the
movable portion, the first control valve can not operate. Further,
for example, when members constituting the first control vale are
broken, the first control valve can not operate.
If the first control valve can not operate normally, the opening
degree of the first control valve can not change sufficiently when
the opening degree is tried to be changed from the first opening
degree to the second opening degree. Consequently, when the first
control valve is abnormal, such as when the first control valve can
not operate at all, the energy supplied to each of the first
turbine and the second turbine remains unchanged. At this time, the
supercharging-pressure-corresponding-value also remains
unchanged.
In view of the above, the control valve abnormality determination
means determines that "the first control valve is abnormal" when
"the absolute value of the difference between the second value and
the first value" is smaller than the first control valve
abnormality determination threshold value.
It should be noted that "the first control valve abnormality
determination threshold value" is preferably set at an appropriate
certain value which allows the control valve abnormality
determination means to determine that the first control valve is
abnormal, when the absolute value of the difference between the
second value and the first value is smaller than the first control
valve abnormality determination threshold value.
Further, the control valve abnormality determination means may be
configured in such a manner that it "infers" that "the second
control valve is normal" when it determines that "the first control
valve is abnormal".
As described above, in the apparatus for determining an abnormality
of a control valve of the present invention, the first control
valve and the second control valve are operated in such a manner
that "at least the first compressor compresses the air introduced
into the first compressor and discharges the compressed air" when
the abnormality determining condition is satisfied.
The second control valve is disposed in the second passage section,
whose one end is connected to the intake air passage between the
first compressor and the second compressor, and whose the other end
is connected to the intake air passage at the downstream side of
the first compressor. Accordingly, the amount of air passing
through the second passage section becomes smaller, and the amount
of air introduced into the first compressor becomes larger, as the
opening degree of the second control vale becomes smaller.
Therefore, the first compressor can "compresses the air introduced
into the first compressor and discharges the compressed air" with
more certainty, as the opening degree of the second control vale
becomes smaller. It is thus preferable that the second control
valve be operated so as to shut (i.e., completely close) the second
passage section when the engine is operated in the predetermined
operating area.
Furthermore, it is preferable that the second control valve be
configured in such a manner that it can adjust the amount of the
air introduced into the first compressor by varying the flow
passage area of the second passage section depending on the opening
degree of the second control valve.
Accordingly, as one of embodiments of the second control valve, a
control valve which comprises "a valving element", "a valve seat
portion" against which the valving element rests, and "biasing
means" for biasing the valving element toward the valve seat
portion, may be adopted. Specifically, the control valve may be
configured in such a manner that the valving element is moved to "a
first position at which the valving element rests against the valve
seat portion" by an biasing force generated by the biasing means so
as to close the second passage section, when "a pressure of an air
in the second passage section at an upstream side of the second
control valve is not larger than a pressure of an air in the second
passage section at an downstream side of the second control valve
by a predetermined pressure or more". Further, the control valve
may be configured in such a manner that the valving element is
moved to "a second position different from the first position"
against the biasing force generated by the biasing means so as to
"increase the flow passage area of the second passage section",
when "the pressure of the air in the second passage section at the
upstream side of the second control valve is larger than the
pressure of the air in the second passage section at the downstream
side of the second control valve by the predetermined pressure or
more".
As another one of embodiments of the second control valve, a
control valve (so called, a butterfly valve) which comprises a
valving element which is rotatably movable around a predetermined
axis may be adopted. Specifically, the control valve may be
configured so as to close the second passage section when the
valving member is at a first rotating position. The control valve
may be configured so as to increase the flow passage area of the
second passage when the valving member rotates toward a second
rotating position different from the first rotating position.
As described above, in order to determine whether or not the second
control valve is abnormal, the control valve abnormality
determination means is configured so as to change the opening
degree of the first control valve from a certain opening degree
(the first opening degree) at a predetermined timing (the first
timing) to another opening degree (the second opening degree)
different from the certain opening degree at the predetermined
timing.
In one of embodiments of the apparatus for determining an
abnormality of a control valve which can change the opening degree
of the first control valve as described above,
the first control valve may be configured so as to include "first
control valve driving means for varying the opening degree of the
first control valve to change the flow passage area of the first
passage section in response to an instruction signal", and
the control valve abnormality determination means may be configured
so as to "change the opening degree of the first control valve by
sending the instruction signal to the first control valve driving
means".
Further, a torque variation and the like, which an operator of the
engine does not expect, may occur, when the control valve
abnormality determination means changes the opening degree of the
first control valve as described above.
In view of the above, it is preferable that the abnormality
determining condition be a condition that is satisfied at least
when "the engine is operated in a deceleration state in which a
torque required for the engine is smaller than or equal to a
predetermined torque".
Even if the opening degree of the first control valve is changed
when the engine is being operated in "the deceleration state", the
output torque variation of the engine may occur, however, it is
unlikely that the operator realizes such a torque variation as the
unexpected/unintentional torque variation. Accordingly, the
apparatus for determining an abnormality of a control valve of the
present invention can determine whether or not the second control
valve (and further the first control valve) is abnormal while
retaining an excellent comfortability in riding.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an internal combustion engine to
which a control apparatus of a present invention is applied;
FIG. 2 is a schematic figure showing a relation among an engine
rotational speed, a fuel injection amount, and a turbo mode,
adopted by the control apparatus of the present invention;
FIG. 3 is a schematic diagram showing one example of an intake air
passage and an exhaust gas passage of an internal combustion engine
to which a control apparatus according to an embodiment of the
present invention is applied;
FIG. 4 is a time-line chart showing a change in a supercharging
pressure with respect to a change in an opening degree of an
exhaust gas changeover valve in the internal combustion engine
shown in FIG. 3;
FIG. 5 is a schematic diagram showing another example of an intake
air passage and an exhaust gas passage of the internal combustion
engine to which the control apparatus according to the embodiment
of the present invention is applied;
FIG. 6 is a time-line chart showing a change in a supercharging
pressure with respect to a change in an opening degree of the
exhaust gas changeover valve in the internal combustion engine
shown in FIG. 5;
FIG. 7 is another time-line chart showing a change in a
supercharging pressure with respect to a change in an opening
degree of the exhaust gas changeover valve in the internal
combustion engine to which the control apparatus according to the
embodiment of the present invention is applied;
FIG. 8 is a flowchart showing a routine executed by a CPU of the
control apparatus according to the embodiment of the present
invention;
FIG. 9 is a flowchart showing a routine executed by the CPU of the
control apparatus according to the embodiment of the present
invention;
FIG. 10 is a flowchart showing a routine executed by the CPU of the
control apparatus according to the embodiment of the present
invention; and
FIG. 11 is a schematic diagram of an example of a structure of the
intake air changeover valve which the control apparatus of the
present invention can adopt.
BEST MODE FOR CARRYING OUT THE INVENTION
Next will be described embodiments of an apparatus for determining
an abnormality of a control valve according to the present
invention with reference to the drawings.
A First Embodiment
An Outline of an Apparatus
FIG. 1 shows a schematic configuration of a system including an
internal combustion engine 10 to which an apparatus for determining
an abnormality of a control valve (hereinafter, this apparatus will
be referred to as "a first apparatus") according to a first
embodiment of the present invention is applied. The engine 10 is a
four cylinder diesel engine.
The engine 10 comprises: an engine main body 20 including a fuel
supply system; an intake system 30 for introducing an air into the
engine main body 20; an exhaust system 40 for emitting an exhaust
gas from the engine main body 20 to the outside; an EGR apparatus
50 for recirculating the exhaust gas to a side of the intake system
30; and supercharging apparatus 60 for compressing an air
introduced into the engine main body 20 by being driven by an
energy of the exhaust gas.
The engine main body 20 comprises a cylinder head 21 with which the
intake system 30 and the exhaust system 40 are connected. The
cylinder head 21 comprises a plurality of fuel injection devices
22, each of which is disposed at an upper portion of a
corresponding cylinder. Each of the fuel injection devices 22 is
communicated with a fuel tank (not shown) so as to inject a fuel
directly into a combustion chamber of each of the cylinders in
response to an instruction signal from an electrical control
apparatus 80.
The intake system 30 includes: an intake manifold 31 communicated
with each of the cylinders through intake ports (not shown)
provided in the cylinder head 21; an intake pipe 32 connected to an
upstream merged portion of the intake manifold 31; a throttle valve
33, in the intake pipe 32, for varying a cross-sectional opening
area of an intake air passage; a throttle valve actuator 33a for
rotatably driving the throttle valve 33 in response to an
instruction signal from the electrical control apparatus 80; an
intercooler 34 disposed in the intake pipe 32 at an upstream side
of the throttle valve 33; and an air cleaner 35 disposed at an end
potion of the intake pipe 32 which is an upstream side of the
supercharging apparatus 60 disposed at an upstream side of the
intercooler 34. The intake manifold 31 and the intake pipe 32
constitute the intake air passage.
The exhaust system 40 comprises: an exhaust manifold 41
communicated with each of the cylinders through exhaust ports (not
shown) provided in the cylinder head 21; an exhaust pipe 42
connected to a downstream merged portion of the exhaust manifold
41; and a well-known catalytic converter for purifying the exhaust
gas (DPNR) 43 disposed in the exhaust pipe 42 at a downstream side
of the supercharging apparatus 60 disposed in the exhaust pipe 42.
The exhaust manifold 41 and the exhaust pipe 42 constitute an
exhaust gas passage.
The EGR apparatus 50 comprises: an exhaust gas recirculation pipe
51 constituting a passage (an EGR passage) for recirculating the
exhaust gas from the exhaust manifold 41 to the intake manifold 31;
an EGR gas cooling apparatus (an EGR cooler) 52 disposed in the
exhaust gas recirculation pipe 51; and an EGR control valve 53
disposed in the exhaust gas recirculation pipe 51. The EGR control
valve 53 is configured so as to be able to vary an amount of the
exhaust gas which is recirculated from the exhaust manifold 41 to
the intake manifold 31 in response to an instruction signal from
the electrical control apparatus 80.
The supercharging apparatus 60 comprises: a high pressure
supercharger (turbocharger) 61 serving as a first supercharger; and
a low pressure supercharger (turbocharger) 62 serving as a second
supercharger. That is, the supercharging apparatus 60 comprises a
plurality (two) of superchargers.
The high pressure supercharger 61 comprises a high pressure
compressor 61a and a high pressure turbine 61b. The high pressure
compressor 61a will be referred to as a first compressor. The high
pressure compressor 61a is disposed in the intake air passage
(intake pipe 32). The high pressure turbine 61b will be referred to
as a first turbine. The high pressure turbine 61b is disposed in
the exhaust gas passage (exhaust pipe 42). The high pressure
compressor 61a and the high pressure turbine 61b are connected with
each other coaxially rotatably through a rotor shaft (not shown).
Accordingly, when the high pressure turbine 61b is driven by the
exhaust gas, the high pressure compressor 61a rotates to compress
an air introduced into the high pressure compressor 61a (i.e.,
supercharge the engine 10).
The low pressure supercharger 62 comprises a low pressure
compressor 62a and a low pressure turbine 62b. The low pressure
compressor 62a will be referred to as a second compressor. The low
pressure compressor 62a is disposed in the intake air passage
(intake pipe 32) at an upstream side of the high pressure
compressor 61a. The low pressure turbine 62b is disposed in the
exhaust gas passage (exhaust pipe 42) at a downstream side of the
high pressure turbine 61b. The low pressure compressor 62a and the
low pressure turbine 62b are connected with each other coaxially
rotatably through a rotor shaft (not shown). Accordingly, when the
low pressure turbine 62b is driven by the exhaust gas, the low
pressure compressor 62a rotates to compress an air introduced into
the low pressure compressor 62a (i.e., supercharge the engine 10).
In this manner, the high pressure supercharger 61 and the low
pressure supercharger 62 are connected in series with each
other.
Further, a capacity of the low pressure supercharger 62 is larger
than a capacity of the high pressure supercharger 61. Accordingly,
a choked flow rate of the low pressure supercharger 62 is larger
than a choked flow rate of the high pressure supercharger 61, and a
surge flow rate of the low pressure supercharger 62 is larger than
a surge flow rate of the high pressure supercharger 61. In other
words, a minimum magnitude of energy required for supercharging the
engine by the high pressure supercharger 61 is smaller than a
minimum magnitude of energy required for supercharging the engine
by the low pressure supercharger 62.
Consequently, the high pressure supercharger 61 and the low
pressure supercharger 62 can supercharge the engine mainly by the
high pressure supercharger 61 in a low load operating area, and
supercharge the engine mainly by the low pressure supercharger 62
in a high load operating area. Accordingly, a new air is
appropriately compressed (the engine is appropriately supercharged)
in a wider operating (load) area by the high pressure supercharger
61 and the low pressure supercharger 62.
Further, the supercharging apparatus 60 comprises: a
high-pressure-compressor-bypass-passage-section (bypass pipe) 63;
an intake air changeover valve (ACV) 64; a
high-pressure-turbine-bypass-passage-section (bypass pipe) 65; an
exhaust gas changeover valve (ECV) 66; a
low-pressure-turbine-bypass-passage (bypass pipe) 67; and an
exhaust gas bypass valve (EBV) 68.
One end of the high-pressure-compressor-bypass-passage-section 63
is connected to the intake air passage (intake pipe 32) between the
high pressure compressor 61a and the low pressure compressor 62a.
The other end of the
high-pressure-compressor-bypass-passage-section 63 is connected to
the intake air passage (intake pipe 32) at a downstream side of the
high pressure compressor 61a. That is, the
high-pressure-compressor-bypass-passage-section 63 constitutes a
passage which bypasses the high pressure compressor 61a. The
high-pressure-compressor-bypass-passage-section 63 will be referred
to as "a second passage section", for convenience.
The intake air changeover valve 64 is a butterfly valve disposed in
the high-pressure-compressor-bypass-passage-section 63. The intake
air changeover valve 64 is configured in such a manner that an
opening degree (operating amount) of the valve 64 is varied by an
intake air changeover valve actuator 64a which is driven in
response to an instruction from the electric control apparatus 80.
The intake air changeover valve 64 changes a flow passage area of
the high-pressure-compressor-bypass-passage-section 63 in
accordance with a change in the opening degree to thereby change a
ratio between an amount of the air introduced into the high
pressure compressor 61a and an amount of the air passing through
the high-pressure-compressor-bypass-passage-section 63. The intake
air changeover valve 64 will be referred to as "a second control
valve", for convenience.
One end of the high-pressure-turbine-bypass-passage-section 65 is
connected to the exhaust gas passage (exhaust pipe 42) at an
upstream side of the high pressure turbine 61b. The other end of
the high-pressure-turbine-bypass-passage-section 65 is connected to
the exhaust gas passage (exhaust pipe 42) between the high pressure
turbine 61b and the low pressure turbine 62b. That is, the
high-pressure-turbine-bypass-passage-section 65 constitutes a
passage which bypasses the high pressure turbine 61b. The
high-pressure-turbine-bypass-passage-section 65 will be referred to
as "a first passage section", for convenience.
The exhaust gas changeover valve 66 is a butterfly valve disposed
in the high-pressure-turbine-bypass-passage-section 65. The exhaust
gas changeover valve 66 is configured in such a manner that an
opening degree (operating amount) of the valve 66 is varied by an
exhaust gas changeover valve actuator 66a which is driven in
response to an instruction from the electric control apparatus 80.
The exhaust gas changeover valve 66 changes a flow passage area of
the high-pressure-turbine-bypass-passage-section 65 in accordance
with a change in the opening degree to thereby change a ratio
between an amount of the gas introduced into the high pressure
turbine 61b and an amount of the gas passing through the
high-pressure-turbine-bypass-passage-section 65. The exhaust gas
changeover valve 66 will be referred to as "a first control valve",
for convenience.
One end of the low-pressure-turbine-bypass-passage-section 67 is
connected to the exhaust gas passage (exhaust pipe 42) at an
upstream side of the low pressure turbine 62b. The other end of the
low-pressure-turbine-bypass-passage-section 67 is connected to the
exhaust gas passage (exhaust pipe 42) at a downstream side of the
low pressure turbine 62b. That is, the
low-pressure-turbine-bypass-passage-section 67 constitutes a
passage which bypasses the low pressure turbine 62b. The
low-pressure-turbine-bypass-passage-section 67 will be referred to
as "a third passage section", for convenience.
The exhaust gas bypass valve 68 is a butterfly valve disposed in
the low-pressure-turbine-bypass-passage-section 67. The exhaust gas
bypass valve 68 is configured in such a manner that an opening
degree (operating amount) of the valve 68 is varied by an exhaust
gas bypass valve actuator 68a which is driven in response to an
instruction from the electric control apparatus 80. The exhaust gas
bypass valve 68 changes a flow passage area of the
low-pressure-turbine-bypass-passage-section 67 in accordance with a
change in the opening degree to thereby change a ratio between an
amount of the gas introduced into the low pressure turbine 62b and
an amount of the gas passing through the
low-pressure-turbine-bypass-passage-section 67. The exhaust gas
bypass valve 68 will be referred to as "a third control valve", for
convenience.
Further, the first apparatus comprises a hot wire airflow meter 71,
a between-compressors-pressure sensor 72, an intake air temperature
sensor 73, a supercharging pressure sensor 74, a crank position
sensor 75, an exhaust gas changeover valve opening degree sensor
76, and an accelerator opening degree sensor 77.
The airflow meter 71 is configured so as to output a signal
indicative of a mass flow rate Ga of the intake air flowing in the
intake pipe 32 (the mass flow rate Ga being an amount of an air
introduced into the engine 10 per unit time and referred simply to
as "a flow rate").
The between-compressors-pressure sensor 72 is configured so as to
output a signal indicative of a pressure
(between-compressors-pressure) in the intake pipe 32 between the
high pressure compressor 61a and the low pressure compressor 62a.
It should be noted that the between-compressors-pressure sensor 72
may be disposed in the
high-pressure-compressor-bypass-passage-section 63 at the upstream
side of the intake air changeover valve 64.
The intake air temperature sensor 73 is configured so as to output
a signal indicative of a temperature of the air flowing in the
intake pipe 32.
The supercharging pressure sensor 74 is disposed in the intake pipe
32 at a downstream side of the throttle valve. The supercharging
pressure sensor 74 is configured so as to output a signal
indicative of a pressure Pim of an air in the intake pipe 32 at a
position at which the supercharging pressure sensor 74 is disposed.
That is, the supercharging pressure sensor 74 outputs a signal
indicative of the pressure (supercharging pressure) Pim of the air
introduced into combustion chambers of the engine 10.
The crank position sensor 75 is configured so as to output a signal
which includes a narrow pulse generated every time a crank shaft
(not shown) rotates 10.degree. and a wide pulse generated every
time the crank shaft rotates 360.degree..
The exhaust gas changeover valve opening degree sensor 76 is
configured so as to output a signal indicative of an opening degree
Oecv of the exhaust gas changeover valve 66.
The accelerator opening degree sensor 77 is configured so as to
output a signal indicative of an opening degree Accp of an
accelerator pedal AP operated by a driver.
The electric control apparatus 80 is a microcomputer, which
includes the following mutually bus-connected elements: a CPU 81; a
ROM 82; a RAM 83; a backup RAM 84 which stores data while power is
held on and which retains the stored data even while power is held
off; and an interface 85 including an AD converter.
The interface 85 is connected to the sensors etc., so as to send
signals from each of the sensors to the CPU 81. Further, in
accordance with instructions from the CPU 81, the interface 85
sends drive signals (instruction signals) to the fuel injection
devices 22, and each of the actuators (the changeover valve
actuator 64a, the exhaust gas changeover valve actuator 66a, and
the exhaust gas bypass valve actuator 68a, and the like).
<An Outline of Operations of the Apparatus>
Next will be described the outline of operations of the first
apparatus.
The first apparatus determines "a turbo mode" which represents an
operating state of the supercharging apparatus 60 (the high
pressure supercharger 61 and the low pressure supercharger 62)
depending on an operating condition/state of the engine 10.
Further, the first apparatus sends to the exhaust gas changeover
valve actuator 66a an instruction signal to change the opening
degree of the exhaust gas changeover valve 66 to "a predetermined
opening degree for a determination", when a predetermined
abnormality determining condition is satisfied.
In addition, the first apparatus compares a supercharging pressure
at a timing "before" the instruction signal is sent to the exhaust
gas changeover valve actuator 66a with a supercharging pressure at
a timing "after" the instruction signal is sent to the exhaust gas
changeover valve actuator 66a to thereby determine "whether or not
the intake air changeover valve 64 is abnormal" and "whether or not
the exhaust gas changeover valve 66 is abnormal".
Further, in a case where the first apparatus determines that the
intake air changeover valve 64 or the exhaust gas changeover valve
66 is abnormal, the first apparatus notifies the operator of the
engine 10 accordingly, and performs "an emergency operation" in
which a load given to the members constituting the engine 10 is
low. In the meanwhile, in a case where all control valves are
normal, the first apparatus provides no notification to the
operator and performs "a normal operation". These are the outline
of the operations of the first apparatus.
<How to Determine the Turbo Mode>
Next will be described the turbo mode which the first apparatus
adopts and the way to determine the turbo mode, before actual
operations of the present invention are described.
As described above, an amount of energy of the exhaust gas which
allows the high pressure supercharger 61 to operate (to supercharge
the engine) is smaller than an amount of energy of the exhaust gas
which allows the low pressure supercharger 62 to operate (to
supercharge the engine). Therefore, the first apparatus controls
the exhaust gas changeover valve 66 in such a manner that the
exhaust gas is preferentially supplied to the high pressure
supercharger 61, when the energy of the exhaust gas is small (i.e.,
when the load of the engine is small and the flow rate Ga is
small). To the contrary, the first apparatus controls the exhaust
gas changeover valve 66 in such a manner that the exhaust gas is
preferentially supplied to the low pressure supercharger 62, when
the energy of the exhaust gas is large (i.e., when the load of the
engine is large and the flow rate Ga is large).
Further, the first apparatus controls the intake air changeover
valve 64 so as to adjust the amount of the air supplied to the high
pressure supercharger 61. In addition, the first apparatus controls
the exhaust gas bypass valve 68 so as to adjust the magnitude of
the energy of the exhaust gas supplied to the low pressure
supercharger 62.
That is, the first apparatus controls the intake air changeover
valve 64, the exhaust gas changeover valve 66, and the exhaust gas
bypass valve 68 (hereinafter, these valves will be referred to as
"each control valve") in such a manner that the an appropriate
amount of the exhaust gas and an appropriate amount of the air are
supplied to the high pressure supercharger 61 and the low pressure
supercharger 62 in accordance with the operating condition of the
engine 10.
In order to perform such a control, the first apparatus divides
operating conditions of the engine 10 into four areas (operating
areas), and determines operating states of the intake air
changeover valve 64, the exhaust gas changeover valve 66, and the
exhaust gas bypass valve 68, the operating states being suitable
for each of the four operating areas. "The operating state of each
control valve" is determined based on a turbo mode.
The turbo mode is determined as follows.
As shown in FIG. 2(A), the first apparatus stores, in the ROM 82, a
turbo mode table "MapTurbo (NE, Q)" which defines a relation among
"an engine rotational speed NE, a fuel injection amount Q, a the
turbo mode" in advance. Each of the figures "1" to "4" shown in
FIG. 2(A) indicates a turbo mode number. "HP+LP" shown in FIG. 2(A)
indicates that both of the high pressure supercharger 61 and the
low pressure supercharger 62 are operated, and "LP" indicates that
the low pressure supercharger 62 is preferentially operated.
FIG. 2(B) shows an operating state of each control valve in the
each turbo mode. In FIG. 2(B), the "fully close" indicates that an
opening degree of the control valve is set at an opening degree to
shut down (completely close) a passage in which the control valve
is disposed, so that the passage is in a condition where the air or
the exhaust gas can not pass through the passage. On the other
hand, the "fully open" indicates that the opening degree of the
control valve is set at an opening degree to completely/fully open
(to its maximum) the passage in which the control valve is
disposed, so that the passage is in a condition where the air or
the exhaust gas can pass through the passage without being
substantially affected by the control valve. The "open" indicates
that the opening degree of the control valve is set at an opening
degree between "the fully close" and "the fully open", so that the
passage is in a condition where an amount of the air or an amount
of the exhaust gas passing through the passage in which the control
valve is disposed can be varied depending on the opening degree of
the control valve.
It should be noted that, in FIG. 2(B), "ECV" is an abbreviated name
of the exhaust gas changeover valve (the first control valve) 66,
"ACV" is an abbreviated name of the intake air changeover valve
(the second control valve) 64, and "EBV" is an abbreviated name of
the exhaust gas bypass valve (the third control valve) 68.
The first apparatus applies an actual engine rotational speed NE
and an actual fuel injection amount Q to the turbo mode Table
MapTurbo (NE, Q) to thereby determine the turbo mode (the operation
state of the each control valve). Thereafter, the first apparatus
controls the each control valve in accordance with the determined
turbo mode.
<An Abnormality Determination for the Control Valve>
Next will be described methods to determine an abnormality of the
control valve in the first apparatus.
The first apparatus makes a determination as to whether or not
either one of "the intake air changeover valve 64 and the exhaust
gas changeover valve 66" is abnormal, when the engine 10 is
operated in an operating area in which the high pressure
supercharger 61 mainly supercharges the engine 10. The operating
area in which the high pressure supercharger 61 mainly supercharges
the engine 10 substantially coincides with operating areas of the
turbo mode 1 and the turbo mode 2 described above.
<An Abnormality Determination Method 1>
When the engine 10 is operated in the operating area in which "the
high pressure supercharger 61 mainly supercharges the engine 10",
the first apparatus provides an instruction (an
instruction-for-decreasing-opening-degree) to "decrease" the
opening degree of the exhaust gas changeover valve 66 to the
exhaust gas changeover valve 66 (in actuality, to the exhaust gas
changeover valve actuator 66a). The first apparatus compares the
supercharging pressure at the timing before the
instruction-for-decreasing-opening-degree is provided with the
supercharging pressure at the timing after the
instruction-for-decreasing-opening-degree is provided.
Further, the first apparatus determines that "the exhaust gas
changeover valve 66 is abnormal", if the supercharging pressure Pim
does not change by an amount larger than or equal to the
predetermined value when (between before and after) the
instruction-for-decreasing-opening-degree is provided. In other
words, the first apparatus determines that "the exhaust gas
changeover valve 66 is normal", if the supercharging pressure Pim
changes (increases, in this case) by the amount larger than or
equal to the predetermined value when (between before and after)
the instruction-for-decreasing-opening-degree is provided. In
addition, the first apparatus determines that "the intake air
changeover valve 64 is abnormal", if the supercharging pressure Pim
"decreases" when (between before and after) the
instruction-for-decreasing-opening-degree is provided to the
exhaust gas changeover valve 66. Hereinafter, this determination
method will be referred to as "an abnormality determination method
1".
<An Abnormality Determination Method 2>
Furthermore, when the engine 10 is operated in the operating area
in which "the high pressure supercharger 61 mainly supercharges the
engine 10", the first apparatus provides an instruction (an
instruction-for-increasing-opening-degree) to "increase" the
opening degree of the exhaust gas changeover valve 66 to the
exhaust gas changeover valve 66 (in actuality, to the exhaust gas
changeover valve actuator 66a). The first apparatus compares the
supercharging pressure at a timing before the
instruction-for-increasing-opening-degree is provided with the
supercharging pressure at a timing after the
instruction-for-increasing-opening-degree is provided.
Thereafter, the first apparatus determines that "the exhaust gas
changeover valve 66 is abnormal", if the supercharging pressure Pim
does not change by an amount larger than or equal to a
predetermined value when (between before and after) the
instruction-for-increasing-opening-degree is provided. In other
words, the first apparatus determines that "the exhaust gas
changeover valve 66 is normal", if the supercharging pressure Pim
changes (decreases, in this case) by the amount larger than or
equal to the predetermined value when (between before and after)
the instruction-for-increasing-opening-degree is provided. In
addition, the first apparatus determines that "the intake air
changeover valve 64 is abnormal", if the supercharging pressure Pim
"increases" when (between before and after) the
instruction-for-increasing-opening-degree is provided to the
exhaust gas changeover valve 66. Hereinafter, this determination
method will be referred to as "an abnormality determination method
2".
The abnormality determination method 1 and the abnormality
determination method 2 are different in whether the instruction
provided to the exhaust gas changeover valve 66 is the
instruction-for-"decreasing"-opening-degree or the
instruction-for-"increasing"-opening-degree. However, a principle
is common to these abnormality determination methods. Accordingly,
next will be described reasons why it is possible to determine
either one of "the intake air changeover valve 64 and the exhaust
gas changeover valve 66" is abnormal according to the methods in
the following order, with reference to the abnormality
determination method 1 as a representative example.
It should be noted that, as described above, the abnormality
determination methods can be carried out as long as the engine 10
is operated either one of in the turbo mode 1 and in the turbo mode
2. Accordingly, in the following description, it is assumed that
the engine 10 is being operated in "the turbo mode 2", for
convenience. It should be also noted that the first apparatus does
not assume that both of "the intake air changeover valve 64 and the
exhaust gas changeover valve 66" become abnormal at the same time.
In actuality, it is rare that both of "the intake air changeover
valve 64 and the exhaust gas changeover valve 66" become abnormal
at the same time. Accordingly, the assumption that both of "the
intake air changeover valve 64 and the exhaust gas changeover valve
66" does not become abnormal at the same time is practical.
<The Description Order>
(Case 1) A case where both of "the intake air changeover valve 64
and the exhaust gas changeover valve 66" are operating normally
(properly).
(Case 2) A case where the intake air changeover valve 64 is
abnormal and the exhaust gas changeover valve 66 is normal.
(Case 3) A case where the exhaust gas changeover valve 66 is
abnormal and the intake air changeover valve 64 is normal.
<Description>
(Case 1) A case where both of "the intake air changeover valve 64
and the exhaust gas changeover valve 66" are operating
normally.
When the engine is being operated in the turbo mode 2, the exhaust
gas changeover valve 66 and the intake air changeover valve 64 are
operated in such a manner that the high pressure compressor 61a
compresses the air introduced into the high pressure compressor 61a
and discharges the compressed air, and the low pressure compressor
62a compresses the air introduced into the low pressure compressor
62a and discharges the compressed air. More specifically, as shown
in FIG. 2(B), in the turbo mode 2, the intake air changeover valve
(ACV) 64 is controlled so as to be in "the fully open" state, and
the exhaust gas changeover valve (ECV) 66 is controlled so as to be
in "the open" state.
FIG. 3 is a schematic view showing how the high pressure compressor
61a compresses the air introduced into the high pressure compressor
61a, and the low pressure compressor 62a compresses the air
introduced into the low pressure compressor 62a, in the state
described above.
As shown in FIG. 3, a new air A introduced into an intake air
passage 32a (a portion of the intake air passage 32) from an
outside of the engine 10 reaches the low pressure compressor 62a.
Subsequently, the new air A passing through the low pressure
compressor 62a reaches the high pressure compressor 61a through an
intake air passage 32b (another portion of the intake air passage
32) between the low pressure compressor 62a and the high pressure
compressor 61a. Thereafter, the new air A passing through the high
pressure compressor 61a is introduced into the combustion chambers
CC of the engine 10 through an intake air passage 32c (still
another portion of the intake air passage 32).
A part of the exhaust gas discharged from the combustion chambers
CC heads to the high pressure turbine 61b after passing through an
exhaust gas passage 42a (a portion of the exhaust gas passage 42).
The other part of the exhaust gas different from the exhaust gas
heading to the high pressure turbine 61b simultaneously heads to
the exhaust gas changeover valve 66 after passing through the
high-pressure-turbine-bypass-passage-section 65. The part of the
exhaust gas Ex which heads to the high pressure turbine 61b passes
through the high pressure turbine 61b, and thereafter merges with
the other part of the exhaust gas Ex passing through the exhaust
gas changeover valve 66. Subsequently, the merged exhaust gas Ex
reaches the low pressure turbine 62b after passing through an
exhaust gas passage 42b (another portion of the exhaust gas passage
42) between the high pressure turbine 61b and the low pressure
turbine 62b. Thereafter, the exhaust gas Ex passing through the low
pressure turbine 62b is discharged through an exhaust gas passage
42d (still another portion of the exhaust gas passage 42) to the
outside of the engine 10.
Consequently, the high pressure turbine 61b is driven by the energy
of "the exhaust gas Ex passing through the high pressure turbine
61b", and the high pressure compressor 61a is thereby driven. As a
result, the high pressure compressor 61a compresses "the new air A
passing through the high pressure compressor 61a".
At the same time, the low pressure turbine 62b is driven by the
energy of "the exhaust gas Ex passing through the low pressure
turbine 62b", and the low pressure compressor 62a is thereby
driven. As a result, the low pressure compressor 62a compresses
"the new air A passing through the low pressure compressor
62a".
It should be noted that the first apparatus performs a feedback
control of the exhaust gas changeover valve 66 in the turbo mode 2
in such a manner that the supercharging pressure Pim which is
obtained from the supercharging pressure sensor 74 coincides with a
target supercharging pressure which is determined in accordance
with the operating condition of the engine 10.
In this manner, when both of the intake air changeover valve 64 and
the exhaust gas changeover valve 66 operate normally, both of the
high pressure compressor 61a and the low pressure compressor 62a
can compress the new air A.
As described above, the first apparatus performs the abnormality
determination by providing the
instruction-for-decreasing-opening-degree to the exhaust gas
changeover valve 66, and by comparing the supercharging pressure at
the timing before the instruction-for-decreasing-opening-degree is
provided with the supercharging pressure at the timing after the
instruction-for-decreasing-opening-degree is provided. Therefore, a
change in the supercharging pressure when the opening degree of the
exhaust gas changeover valve 66 is changed (decreased) will be
described with reference to a time-line chart shown in FIG. 4.
FIG. 4 is the time-line chart showing a relation among the opening
degree Oecv of the exhaust gas changeover valve 66, the
supercharging pressure Pim, a pressure ratio of the high pressure
supercharger PRhp, and a pressure ratio of the low pressure
supercharger PRlp. The pressure ratio of the high pressure
supercharger PRhp is a ratio of "a pressure of the new air A
immediately after the new air A has passed through the high
pressure compressor 61a" to "a pressure of the new air A
immediately before the new air A is introduced into the high
pressure compressor 61a" The pressure ratio of the low pressure
supercharger PRlp is a ratio of "a pressure of the new air A
immediately after the new air A has passed through the low pressure
compressor 62a" to "a pressure of the new air A immediately before
the new air A is introduced into the low pressure compressor 62a".
Accordingly, the supercharging pressure Pim varies in accordance
with "a product of the pressure ratio of the high pressure
supercharger PRhp and the pressure ratio of the low pressure
supercharger PRlp".
In the example shown in FIG. 4, the opening degree Oecv of the
exhaust gas changeover valve 66 is kept at a certain opening degree
Oecv1 for a period from time t0 to time t1. During this period,
each of the supercharging pressure Pim, the pressure ratio of the
high pressure supercharger PRhp, and the pressure ratio of the low
pressure supercharger PRlp is kept at a respective certain
value.
Subsequently, the first apparatus sends to the exhaust gas
changeover valve 66 at the time t1 an instruction to change the
opening degree of the exhaust gas changeover valve 66 to an opening
degree Oecv2. As a result, the opening degree Oecv of the exhaust
gas changeover valve 66 starts to decrease from the opening degree
Oecv1 at the time t1, and reaches the opening degree Oecv2 at time
t2. Further, the first apparatus keeps the opening degree Oecv of
the exhaust gas changeover valve 66 at the opening degree Oecv2
after the time t2.
When the opening degree Oecv of the exhaust gas changeover valve 66
decreases as described above, the amount of the exhaust gas Ex
which can pass through the
high-pressure-turbine-bypass-passage-section 65 decreases, and the
amount of the exhaust gas Ex which heads to the high pressure
turbine 61b increases. This increases the energy of the exhaust gas
Ex supplied to the high pressure turbine 61b, and thereby the
pressure ratio of the high pressure supercharger PRhp
"increases".
On the other hand, the amount of the exhaust gas Ex which can pass
through the high-pressure-turbine-bypass-passage-section 65
decreases, when the opening degree Oecv of the exhaust gas
changeover valve 66 decreases. Accordingly, the amount of the
exhaust gas Ex which directly flowing into the low pressure turbine
62b decreases. This decreases the energy supplied to the low
pressure turbine 62b, and the pressure ratio of the low pressure
supercharger PRlp thereby "decreases".
As described above, the current operating condition is in the turbo
mode 2, and is in the state in which the high pressure supercharger
61 can compress the new air more efficiently than the low pressure
supercharger 62 (i.e., the state where the high pressure
supercharger 61 mainly supercharge the engine). Accordingly, as
shown in FIG. 4, when the opening degree Oecv of the exhaust gas
changeover valve 66 decreases, an increasing amount (X) in the
pressure ratio of the high pressure supercharger PRhp becomes
larger than a decreasing amount (Y) in the pressure ratio of the
low pressure supercharger PRlp. Consequently, the supercharging
pressure Pim which varies in accordance with the product of the
pressure ratio of the high pressure supercharger PRhp and the
pressure ratio of the low pressure supercharger PRlp "increases" by
an amount larger than or equal to a threshold supercharging
pressure Pimth.
As described above, in the case where both of the exhaust gas
changeover valve 66 and the intake air changeover valve 64 "operate
normally", the supercharging pressure Pim "increases" by the amount
larger than or equal to the threshold supercharging pressure Pimth,
when the opening degree Oecv of the exhaust gas changeover valve 66
is "decreased". It can be understood from the above description
that the supercharging pressure Pim "decreases" by the amount
larger than or equal to the threshold supercharging pressure Pimth,
when the opening degree Oecv of the exhaust gas changeover valve 66
is "increased".
(Case 2) A case where the intake air changeover valve 64 is
abnormal and the exhaust gas changeover valve 66 is normal.
Next will be described a case where "the intake air changeover
valve 64" is abnormal among the intake air changeover valve 64 and
the exhaust gas changeover valve 66, with reference to FIG. 5. As
described above, in the case where the engine 10 is being operated
in the turbo mode 2, the intake air changeover valve 64 must be in
"the fully close" state, if the intake air changeover valve 64
operates normally. Accordingly, hereinafter, a description will be
continued based on an assumption that "an abnormal state is
occurring in which the opening degree of the intake air changeover
valve 64 is larger than or equal to a certain opening degree which
causes the intake air changeover valve 64 to produce no throttle
effect (e.g., "the fully open").revreaction.. Hereinafter, this
abnormal state will be referred to as "an abnormal open state".
In this state, as shown in FIG. 5, the exhaust gas discharged from
the combustion chambers CC is emitted to the outside of the engine
10 via passages similar to ones in "the Case 1" described above.
That is, the exhaust gas Ex is discharged to the outside of the
engine 10 through the high pressure turbine 61b and the low
pressure turbine 62b.
Accordingly, the high pressure turbine 61b is driven. In addition,
high pressure compressor 61a is thereby driven. At the same time,
the low pressure turbine 62b is driven. The low pressure compressor
62a is thereby driven.
In the meantime, the new air A introduced from the outside of the
engine 10 into the intake air passage 32a reaches the low pressure
compressor 62a. Consequently, the low pressure compressor 62a
compresses the new air A. However, since the intake air changeover
valve 64 is in the abnormal open state, the new air A compressed by
the low pressure compressor 62a does not head to the high pressure
compressor 61a, and the new air A is introduced into the combustion
chambers CC of the engine 10 through the
high-pressure-compressor-bypass-passage-section 63. That is, the
high pressure compressor 61a can not further compress the new air A
compressed by the low pressure compressor 62a. In other words, the
engine 10 is supercharged by "the low pressure supercharger 62
only", when the intake air changeover valve 64 is in the abnormal
open state.
Next will be described an operation of the first apparatus when it
performs the abnormality determination in this state, with
reference to a time-line chart shown in FIG. 6. The time-line chart
shown in FIG. 6 is similar to the time-line chart shown in FIG. 4
to show a relation among the plurality of the parameters.
In the example shown in FIG. 6, the opening degree Oecv of the
exhaust gas changeover valve 66 is kept at the certain opening
degree Oecv1 for a period from time t0 to time t1. As described
above, the new air A is not compressed by the high pressure
compressor 61a, but the new air A is compressed by the low pressure
compressor 62a only. Accordingly, during this period, the pressure
ratio of the high pressure supercharger PRhp is "1". Further, the
supercharging pressure Pim is therefore equal to the pressure ratio
of the low pressure supercharger PRlp.
Subsequently, the first apparatus sends to the exhaust gas
changeover valve 66 at the time t1 an instruction to change the
opening degree Oecv to the opening degree Oecv2. As a result, the
opening degree Oecv of the exhaust gas changeover valve 66 starts
to decrease from the opening degree Oecv1 at the time t1, and
reaches the opening degree Oecv2 at time t2. Further, the first
apparatus keeps the opening degree Oecv of the exhaust gas
changeover valve 66 at the opening degree Oecv2 after the time
t2.
As described above, when the opening degree Oecv of the exhaust gas
changeover valve 66 decreases, the energy of the exhaust gas Ex
supplied to the high pressure turbine 61b increases. However, in
the present case (the Case 2), the pressure ratio of the high
pressure supercharger PRhp remains at "1", since the high pressure
compressor 61a can not compress the new air A.
On the other hand, when the opening degree Oecv of the exhaust gas
changeover valve 66 decreases, the energy supplied to the low
pressure turbine 62b decreases as described above. Accordingly, the
pressure ratio of the low pressure supercharger PRlp thereby
"decreases". As a result, the supercharging pressure Pim also
"decreases".
As described above, in the case where the exhaust gas changeover
valve 66 is normal, but "the intake air changeover valve 64 is
abnormal", the supercharging pressure Pim decreases, when the
opening degree Oecv of the exhaust gas changeover valve 66 is
"decreased". It can be understood from the above description that
the supercharging pressure Pim "increases", when the opening degree
Oecv of the exhaust gas changeover valve 66 is "increased".
(Case 3) A case where the exhaust gas changeover valve 66 is
abnormal, and the intake air changeover valve 64 is normal.
Next will be described a case where "the exhaust gas changeover
valve 66" is abnormal among the intake air changeover valve 64 and
the exhaust gas changeover valve 66. Hereinafter, a description
will be continued based on an assumption that "an abnormal state
occurs in which the exhaust gas changeover valve 66 can not
operate/move" due to an adhesion of the exhaust gas changeover
valve 66 and so on, while the engine 10 is being operated in the
turbo mode 2. In the turbo mode 2, the high pressure supercharger
61 and the low pressure supercharger 62 operate in the same way as
in "the Case 1" described above.
Next will be described an operation of the first apparatus when it
performs the abnormality determination in this state, with
reference to a time-line chart shown in FIG. 7. The time-line chart
shown in FIG. 7 is similar to the time-line chart shown in FIG. 4
to show a relation among the plurality of the parameters.
In the example shown in FIG. 7, the opening degree Oecv of the
exhaust gas changeover valve 66 is kept at the certain opening
degree Oecv1 for a period from time t0 to time t1. During this
period, each of the supercharging pressure Pim, the pressure ratio
of the high pressure supercharger PRhp, and the pressure ratio of
the low pressure supercharger PRlp is kept at the respective
certain value.
Subsequently, the first apparatus sends to the exhaust gas
changeover valve 66 at the time t1 an instruction to change the
opening degree of the exhaust gas changeover valve 66 to the
opening degree Oecv2. However, the exhaust gas changeover valve 66
can not operate. Accordingly, the opening degree Oecv of the
exhaust gas changeover valve 66 is kept at the opening degree Oecv1
after the time t1. Consequently, the pressure ratio of the high
pressure supercharger PRhp and the pressure ratio of the low
pressure supercharger PRlp remain unchanged when (between before
and after) the instruction to change the opening degree of the
exhaust gas changeover valve 66 to the opening degree Oecv2 is
sent. As a result, the supercharging pressure Pim also remains
unchanged.
As described above, in the case where the intake air changeover
valve 64 is normal, but "the exhaust gas changeover valve 66 is
abnormal", the supercharging pressure Pim does not change, even
when the instruction to change the opening degree of the exhaust
gas changeover valve 66 is provided to the exhaust gas changeover
valve 66.
It is understood from the above description that the supercharging
pressure Pim changes differently from each other depending on each
case of the Case 1 to the Case 3, when the instruction to change
the opening degree Oecv of the exhaust gas changeover valve 66 is
provided. Accordingly, it is possible to determine whether or not
either one of "the intake air changeover valve 64 and the exhaust
gas changeover valve 66" is abnormal, according to the abnormality
determination methods 1 and 2.
<An Actual Operation>
Next will be described an actual operation of the first
apparatus.
The CPU 81 executes "an abnormality determination routine" shown by
a flowchart in FIG. 8 every elapse of a predetermined time
period.
The CPU 81 starts executing the routine from step 800 of FIG. 8 and
proceeds to step 805 at which the CPU 81 determines whether or not
a predetermined abnormality determining condition is satisfied.
At step 805, the CPU 81 determines that the abnormality determining
condition is satisfied when all of the following conditions are
satisfied, and determines that the abnormality determining
condition is not satisfied when one or more of the following
conditions are not satisfied.
(Condition 1) An operating state of the engine 10 is the turbo mode
1 or the turbo mode 2.
(Condition 2) The flow rate (the flow rate of the intake air) Ga is
smaller than or equal to a predetermined threshold-flow-rate
Gath.
(Condition 3) A torque required for the engine 10 is smaller than
or equal to a predetermined threshold-required-torque (the engine
10 is being operated in a deceleration state.).
That is, the abnormality determining condition is satisfied, when
both conditions are satisfied, one condition being satisfied when
the engine 10 is being operated in the operating area where "the
first supercharger" can mainly supercharge the engine 10 among the
first supercharger and the second supercharger, and the other
condition being satisfied when the engine 10 is being operated in
the deceleration state.
It should be noted that only either one of the condition 1 and the
condition 2 can be adopted, if the condition 2 is automatically
satisfied when the condition 1 is satisfied. In addition, the
condition 3 may be omitted. "The predetermined threshold-flow-rate
Gath" used in the condition 2 is set at a certain flow rate such
that the engine is supercharged mainly by the high pressure
supercharger 61 when the flow rate Ga is smaller than or equal to
the certain flow rate.
The threshold-flow-rate Gath may be set at a certain flow rate such
that the low pressure supercharger 62 does not supercharge the
engine when the flow rate Ga is smaller than or equal to the
certain flow rate. In this case, it is preferable that the
threshold-flow-rate Gath be set at a certain flow rate such that
both the high pressure supercharger 61 and the low pressure
supercharger 62 supercharge the engine, when the flow rate Ga is
larger than or equal to the certain flow rate. Further, the
threshold-flow-rate Gath may be set at a certain flow rate such
that the high pressure supercharger 61 mainly supercharge the
engine and the low pressure supercharger 62 also supercharge the
engine, when the flow rate Ga is smaller than or equal to the
certain flow rate, although the low pressure supercharger 62 can
not mainly supercharge the engine.
The required torque used in the condition 3 can be determined based
on "the opening degree Accp of the accelerator pedal", "the engine
rotational speed NE", and "the fuel supply amount Q", and so on. In
other words, the condition 3 may be a condition which is satisfied
when the opening degree Accp of the accelerator pedal is smaller
than or equal to a predetermined threshold-opening-degree Accpth,
or may be a condition which is satisfied when an operating
condition determined by the opening degree Accp of the accelerator
pedal and the engine rotational speed NE is in "a predetermined
deceleration area defined based on the opening degree Accp of the
accelerator pedal and the engine rotational speed NE", or may be a
condition which is satisfied when the fuel supply amount Q
determined based on the opening degree Accp of the accelerator
pedal and the engine rotational speed NE, and so on, is smaller
than or equal to "a predetermined threshold fuel supply amount
representing the deceleration condition".
Further, the abnormality determining condition may include a
condition that "the determination as to whether or not the control
valve is abnormal has not been made yet after a start of a current
operation (i.e., after an ignition key switch is turned ON from
OFF).
If the abnormality determining condition is not satisfied at the
present time, the CPU 81 makes a "No" determination at step 805 to
proceed directly to step 895 at which the CPU 81 ends the present
routine tentatively. On the other hand, if the abnormality
determining condition is satisfied at the present time, the CPU 81
makes a "Yes" determination at step 805 to proceed to step 810. At
step 810, the CPU 81 provides to the throttle valve actuator 33a an
instruction to set the opening degree of the throttle valve 33 to a
fully-open opening degree.
Subsequently, the CPU 81 proceeds to step 815 at which the CPU 81
obtains the supercharging pressure Pim at the present time, stores
the obtained supercharging pressure Pim as "a referential
supercharging pressure Pim0 serving as a first value", and proceeds
to step 820. It should be noted that this timing will be referred
to as "a first timing", and the opening degree Oecv of the exhaust
gas changeover valve 66 at the first timing will be referred to as
"a first opening degree Oecv1", for convenience.
Subsequently, at step 820, the CPU 81 provides to the exhaust gas
changeover valve actuator 66a an instruction to change the opening
degree Oecv of the exhaust gas changeover valve 66 to the second
opening degree Oecv2. The CPU 81 thereafter wait till a second
timing which comes when a predetermined time period has elapsed
from the present time. At step 820, if the first opening degree
Oecv1 is smaller than 1/2 (a half) of "a fully-open-opening-degree
OecvMAX which is a maximum opening degree of the exhaust gas
changeover valve 66", the CPU 81 sets the second opening degree
Oecv2 at "an opening degree (for example, the
fully-open-opening-degree OecvMAX) larger than the first opening
degree Oecv1". On the other hand, if the first opening degree Oecv1
is larger than or equal to the 1/2 of "the
fully-open-opening-degree OecvMAX of the exhaust gas changeover
valve 66", the CPU 81 sets the second opening degree Oecv2 at "an
opening degree (for example, the fully-close-opening-degree
OecvCLOSE) smaller than the first opening degree Oecv1".
When the second timing comes, the CPU 81 proceeds to step 825 at
which the CPU 81 obtains the supercharging pressure Pim at the
second timing, and stores the obtained supercharging pressure Pim
as "a supercharging-pressure-for-a-determination Pim1 serving as a
second value". Subsequently, the CPU 81 proceeds to step 830 at
which the CPU 81 determines whether or not an absolute value of a
difference between the supercharging-pressure-for-a-determination
Pim1 and the referential supercharging pressure Pim0 is larger than
or equal to a threshold supercharging pressure Pimth. The threshold
supercharging pressure Pimth is also referred to as a first control
valve abnormality determination threshold value, and is "a
predetermined value larger than or equal to 0" obtained based on
experiments in advance.
(Assumption A) When Both of the Exhaust Gas Changeover Valve 66 and
the Intake Air Changeover Valve 64 are Normal.
Now, it is assumed that both the exhaust gas changeover valve 66
and the intake air changeover valve 64 are normal. In this case, as
described above, the absolute value of the difference between the
supercharging-pressure-for-a-determination Pim1 and the referential
supercharging pressure Pim0 becomes larger than or equal to the
threshold supercharging pressure Pimth.
Accordingly, the CPU 81 makes a "Yes" determination at step 830 to
proceed to step 835 at which the CPU 81 sets a value of an
exhaust-gas-changeover-valve-abnormality-determination-flag XECV at
"0". The
exhaust-gas-changeover-valve-abnormality-determination-flag XECV
indicates that the exhaust gas changeover valve 66 operates
normally, when the value of the flag XECV is "0". The
exhaust-gas-changeover-valve-abnormality-determination-flag XECV
indicates that the exhaust gas changeover valve 66 is abnormal,
when the value of the flag XECV is "1". It should be noted that the
value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
set at "0" by an initial routine executed when the ignition key
switch (not shown) is turned ON from OFF. Further, all of values of
flags which the first apparatus uses, the flags including the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV,
are stored in the back-up RAM 84.
Subsequently, the CPU 81 proceeds to step 840 at which the CPU 81
determines whether or not the second opening degree Oecv2 which is
set at step 820 is smaller than the first opening degree Oecv1.
When the second opening degree Oecv2 is smaller than the first
opening degree Oecv1, the CPU 81 proceeds to step 845 at which the
CPU 81 determines whether or not the
supercharging-pressure-for-a-determination Pim1 (the second value)
is smaller than the referential supercharging pressure Pim0 (the
first value).
According to the assumption A described above, the
supercharging-pressure-for-a-determination Pim1 is larger than the
referential supercharging pressure Pim0, when the second opening
degree Oecv2 is smaller than the first opening degree Oecv1 (i.e.,
when the opening degree Oecv of the exhaust gas changeover valve 66
is decreased) (refer to FIG. 4). Therefore, the CPU 81 makes a
"Yes" determination at step 845 to proceed to step 850 at which the
CPU 81 sets a value of an
intake-air-changeover-valve-abnormality-determination-flag XACV at
"0". The intake-air-changeover-valve-abnormality-determination-flag
XACV indicates that the intake air changeover valve 64 operates
normally, when the value of the flag XACV is "0". The
intake-air-changeover-valve-abnormality-determination-flag XACV
indicates that the intake air changeover valve 64 is abnormal, when
the value of the flag XACV is "1". It should be noted that the
value of the
intake-air-changeover-valve-abnormality-determination-flag XACV is
set at "0" by the initial routine executed when the ignition key
switch (not shown) is turned ON from OFF. Thereafter, the CPU 81
proceeds to step 895 at which the CPU 81 ends the present routine
tentatively.
On the other hand, when the CPU proceeds to step 840, if the second
opening degree Oecv2 is larger than or equal to the first opening
degree Oecv1 (i.e., if the opening degree Oecv of the exhaust gas
changeover valve 66 is increased), the CPU 81 makes a "No"
determination at step 840 to proceed to step 855 at which the CPU
81 determines whether or not the
supercharging-pressure-for-a-determination Pim1 is smaller than the
referential supercharging pressure Pim0.
In this case (i.e., in the case where the opening degree Oecv of
the exhaust gas changeover valve 66 is increased under the
assumption A described above), the
supercharging-pressure-for-a-determination Pim1 is smaller than the
referential supercharging pressure Pim0, as described. Accordingly,
the CPU 81 makes a "Yes" determination at step 855 to proceed to
step 850 at which the CPU 81 sets the
intake-air-changeover-valve-abnormality-determination-flag XACV at
"0".
Further, the CPU 81 executes "an abnormality notifying routine"
shown by a flowchart in FIG. 9 every elapse of a predetermined time
period. When the intake air changeover valve 64 or the exhaust gas
changeover valve 66 is abnormal, the CPU 81 notifies an operator of
the engine 10 accordingly, by this routine.
More specifically, the CPU 81 starts executing the routine from
step 900 in FIG. 9 and proceeds to step 910 at which the CPU 81
determines whether or not the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
"0". The value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
"0" at the present time, the CPU 81 therefore makes a "Yes"
determination to proceed to step 920.
Subsequently, at step 920, the CPU 81 determines whether or not the
value of the
intake-air-changeover-valve-abnormality-determination-flag XACV is
"0". The value of the
intake-air-changeover-valve-abnormality-determination-flag XACV is
"0" at the present time, the CPU 81 therefore makes a "Yes"
determination to proceed to step 930.
At step 930, the CPU 81 sets a value of an
abnormality-occurrence-flag XEMG at "0". The
abnormality-occurrence-flag XEMG indicates that both the intake air
changeover valve 64 and the exhaust gas changeover valve 66 operate
normally, when the value of the flag XEMG is "0". The
abnormality-occurrence-flag XEMG indicates that the intake air
changeover valve 64 or the exhaust gas changeover valve 66 is
abnormal, when the value of the flag XEMG is "1". It should be
noted that the value of the abnormality-occurrence-flag XEMG is set
at "0" by the initial routine executed when the ignition key switch
(not shown) is turned ON from OFF.
Subsequently, the CPU proceeds to step 995 at which the CPU 81 ends
the present routine tentatively. Accordingly, when both the intake
air changeover valve 64 and the exhaust gas changeover valve 66 are
normal (or when both the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV
and the value of the
intake-air-changeover-valve-abnormality-determination-flag XACV are
"0"), a warning is not provided.
In addition, the CPU 81 executes "a fuel supply control routine"
shown by a flowchart in FIG. 10 every time when a crank angle of
any one of the cylinders coincides with a predetermined crank angle
.theta.g (e.g., 90.degree. crank angle before a compression top
dead center). The CPU 81 calculates the fuel injection amount Q and
instructs to inject the fuel, by this routine. The cylinder whose
crank angle coincides with the predetermined crank angle .theta.g
before the compression top dead center will be referred to as "a
fuel injection cylinder", hereinafter.
More specifically, when any one of the cylinders coincides with the
predetermined crank angle .theta.g, the CPU 81 starts executing the
routine from step 1000 in FIG. 10, and proceeds to step 1010 at
which the CPU 81 determines whether or not the value of the
abnormality-occurrence-flag XEMG is "0". The value of the
abnormality-occurrence-flag XEMG is "0" at the present time, the
CPU 81 therefore makes a "Yes" determination at step 1010 to
proceed to step 1020.
At step 1020, the CPU 81 obtains the opening degree Accp of the
accelerator pedal based on the output value of the accelerator
opening degree sensor 77, and obtains the engine rotational speed
NE based on the output value of the crank position sensor 75. Then,
the CPU 81 applies the opening degree Accp of the accelerator pedal
at the present time and the engine rotational speed NE at the
present time to a
normal-operating-state-fuel-injection-amount-table MapMain (Accp,
NE) so as to obtain a fuel injection amount Q, the table MapMain
(Accp, NE) defining a relation among "the opening degree Accp of
the accelerator pedal, the engine rotational speed NE, and the fuel
injection amount Q" when all of the control valves are normal, and
the table MapMain (Accp, NE) being defined in advance. The fuel
injection amount Q when all of the control valves are normal
corresponds to a required torque. Hereinafter, an operation in
which the fuel injection amount determined by the
normal-operating-state-fuel-injection-amount-table MapMain (Accp,
NE) is used will be referred to as "a normal operation".
Subsequently, the CPU 81 proceeds to step 1030 at which the CPU 81
provides to the injector 22 disposed for the fuel injection
cylinder an instruction to inject the fuel whose amount is the fuel
injection amount Q from the injector 22. That is, at this time, the
fuel whose amount is the fuel injection amount Q is supplied to the
fuel injection cylinder. The CPU 81 thereafter proceeds to step
1095 at which the CPU 81 ends the present routine tentatively.
In this manner, the first apparatus performs "the normal operation"
in which the fuel whose amount is equal to the fuel injection
amount Q determined based on the
normal-operating-state-fuel-injection-amount-table MapMain (Accp,
NE) is injected to the fuel injection cylinder, when both the
intake air changeover valve 64 and the exhaust gas changeover valve
66 operate normally.
(Assumption B) When the Exhaust Gas Changeover Valve 66 is Abnormal
and the Intake Air Changeover Valve 64 is Normal.
Next will be described a case where the exhaust gas changeover
valve 66 is abnormal, and therefore the opening degree of the
exhaust gas changeover valve 66 remains unchanged even when an
instruction to change the opening degree of the exhaust gas
changeover valve 66 is provided to the exhaust gas changeover valve
66. In this case, as described above, even when the instruction to
change the opening degree of the exhaust gas changeover valve 66 is
provided to the exhaust gas changeover valve actuator 66a, the
supercharging pressure Pim remains unchanged, and the absolute
value of the difference between the
supercharging-pressure-for-a-determination Pim1 and the referential
supercharging pressure Pim0 is therefore smaller than the threshold
supercharging pressure Pimth.
In this case, when the CPU 81 starts executing the routine from
step 800 in FIG. 8 at the predetermined timing, the CPU 81 proceeds
to step 830 through step 805 to step 825, if the abnormality
determining condition is satisfied. According to the assumption B
described above, the supercharging-pressure-for-a-determination
Pim1 and the referential supercharging pressure Pim0 are equal to
each other. The absolute value of the difference between the
supercharging-pressure-for-a-determination Pim1 and the referential
supercharging pressure Pim0 is therefore smaller than the threshold
supercharging pressure Pimth. Accordingly, the CPU 81 makes a "No"
determination at step 830 to proceed to step 860. The CPU 81 sets
the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV at
"1" at step 860, and sets the value of the
intake-air-changeover-valve-abnormality-determination-flag XACV at
"0" at the following step 865. Thereafter, the CPU 81 proceeds to
step 895 at which the CPU 81 ends the present routine
tentatively.
Further, in this case, the CPU 81 starts executing the routine from
step 900 shown in FIG. 9 at the predetermined timing to proceed to
step 910. The value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
"1" at the present time, and the CPU 81 therefore makes a "No"
determination at step 910 to proceed to step 940 at which the CPU
81 notifies the operator of the engine 10 that "the exhaust gas
changeover valve 66 is abnormal" by turning on a warning lamp which
is not shown, or the like. Thereafter, the CPU 81 sets the value of
the abnormality-occurrence-flag XEMG at "1", and proceeds to step
995 at which the CPU 81 ends the present routine tentatively.
As described above, when the exhaust gas changeover valve 66 is
abnormal (i.e., the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
"1"), the warning notifying the operator of the engine 10 that "the
exhaust gas changeover valve 66 is abnormal" is provided.
Further, when the crank angle of any one of the cylinders coincides
with the predetermined crank angle .theta.g, the CPU 81 starts
executing the routine from step 1000 in FIG. 10 and proceeds to
step 1010. The value of the abnormality-occurrence-flag XEMG is "1"
at the present time, and the CPU 81 therefore makes a "No"
determination at step 1010 to proceed to step 1040.
At step 1040, the CPU 81 obtains the opening degree Accp of the
accelerator pedal based on the output value of the accelerator
opening degree sensor 77, and obtains the engine rotational speed
NE based on the output value of the crank position sensor 75. Then,
the CPU 81 applies the opening degree Accp of the accelerator pedal
at the present time and the engine rotational speed NE at the
present time to an
abnormality-occurring-state-fuel-injection-amount-table MapEmg
(Accp, NE) so as to obtain the fuel injection amount Q when the
abnormal state is occurring, the table MapEmg (Accp, NE) defining a
relation among "the opening degree Accp of the accelerator pedal,
the engine rotational speed NE, and the fuel injection amount Q" in
advance, and the table MapEmg (Accp, NE) being used when "the
intake air changeover valve 64 or the exhaust gas changeover valve
66 is abnormal".
The abnormality-occurring-state-fuel-injection-amount-table MapEmg
(Accp, NE) is a table to determine "the fuel injection amount Q
which is unlikely to cause other members of the engine 10 or the
whole engine 10 to be broken, even if the engine 10 is continued to
be operated when the intake air changeover valve 64 or the exhaust
gas changeover valve 66 is abnormal". Accordingly, it should be
appreciated that the fuel injection amount determined based on the
abnormality-occurring-state-fuel-injection-amount-table MapEmg
(Accp, NE) with respect to a certain set of "the opening degree
Accp of the accelerator pedal and the engine rotational speed NE"
is smaller than the fuel injection amount determined based on the
normal-operating-state-fuel-injection-amount-table MapMain (Accp,
NE) with respect to the certain set of "the opening degree Accp of
the accelerator pedal and the engine rotational speed NE".
Hereinafter, an operation in which the fuel supply amount
determined by the
abnormality-occurring-state-fuel-injection-amount-table MapEmg
(Accp, NE) is used will be referred to as "an emergency
operation".
Subsequently, the CPU 81 proceeds to step 1030 at which the CPU 81
to inject the fuel whose amount is the fuel injection amount Q from
the injector 22 disposed for the fuel injection cylinder.
Thereafter, the CPU 81 proceeds to step 1095 at which the CPU 81
ends the present routine tentatively.
As described above, when the exhaust gas changeover valve 66 is
abnormal, the first apparatus notifies the operator of the engine
10 that "the exhaust gas changeover valve 66 is abnormal" and
performs the emergency operation.
(Assumption C) When the Intake Air Changeover Valve 64 is Abnormal,
and the Exhaust Gas Changeover Valve 66 is Normal.
Next will be described a case where the intake air changeover valve
64 is abnormal (the valve 64 is in the abnormal open state). In
this case, as described above, the supercharging pressure Pim
decreases when the opening degree Oecv of the exhaust gas
changeover valve 66 is decreased, and the supercharging pressure
Pim increases when the opening degree Oecv of the exhaust gas
changeover valve 66 is increased. Accordingly, the
supercharging-pressure-for-a-determination Pim1 is smaller than the
referential supercharging pressure Pim0 when the second opening
degree Oecv2 is smaller than the first opening degree Oecv1, the
supercharging-pressure-for-a-determination Pim1 is larger than the
referential supercharging pressure Pim0 when the second opening
degree Oecv2 is larger than the first opening degree Oecv1.
In this sate, the CPU 81 starts executing the routine from step 800
in FIG. 8, and proceeds to step 830 through step 805 to step 825 if
the abnormality determining condition is satisfied. According to
the assumption C described above, the exhaust gas changeover valve
66 operates normally, the absolute value of the difference between
the supercharging-pressure-for-a-determination Pim1 and the
referential supercharging pressure Pim0 is therefore larger than or
equal to the threshold supercharging pressure Pimth. Accordingly,
the CPU 81 makes a "Yes" determination at step 830 to proceed to
step 835 at which the CPU 81 sets the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV at
"0".
Subsequently, if the second opening degree Oecv2 is smaller than
the first opening degree Oecv1 when the CPU 81 proceeds to step
840, the CPU 81 proceeds to step 845. In this case (i.e. in the
case where the opening degree Oecv of the exhaust gas changeover
valve 66 is decreased under the assumption C described above), the
supercharging-pressure-for-a-determination Pim1 is smaller than the
referential supercharging pressure Pim0, as described above.
Accordingly, the CPU 81 makes a "No" determination at step 845 to
proceed to step 870 at which the CPU 81 sets the value of the
intake-air-changeover-valve-abnormality-determination-flag XACV at
"1". Thereafter, the CPU 81 proceeds to step 895 at which the CPU
81 end the present routine tentatively.
On the other hand, if the second opening degree Oecv2 is larger
than or equal to the first opening degree Oecv1 (i.e., if the
opening degree Oecv of the exhaust gas changeover valve 66 is
increased) when the CPU proceeds to step 840, the CPU 81 makes a
"No" determination at step 840 to proceed to step 855. In this case
(i.e. in the case where the opening degree Oecv of the exhaust gas
changeover valve 66 is increased under the assumption C described
above), the supercharging-pressure-for-a-determination Pim1 is
larger than the referential supercharging pressure Pim0, as
described above. Accordingly, the CPU 81 makes a "No" determination
at step 855 to proceed to step 870 at which the CPU 81 sets the
value of the
intake-air-changeover-valve-abnormality-determination-flag XACV at
"1". Thereafter, the CPU 81 proceeds to step 895 at which the CPU
81 ends the present routine tentatively.
Further, in this case, the CPU 81 starts executing the routine from
step 900 in FIG. 9 at the predetermined timing to proceed to step
910. The value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV is
"0" at the present time, and the CPU 81 therefore makes a "Yes"
determination at step 910 to proceed to step 920. The value of the
intake-air-changeover-valve-abnormality-determination-flag XACV is
"1" at the present time, and the CPU 81 therefore makes a "No"
determination at step 920 to proceed to step 960 at which the CPU
81 notifies the operator of the engine 10 that "the intake air
changeover valve 64 is abnormal".
Thereafter, the CPU 81 sets the value of the
abnormality-occurrence-flag XEMG at "1", and proceeds to step 995
at which the CPU 81 ends the present routine tentatively.
Accordingly, when the intake air changeover valve 64 is abnormal
(i.e., the value of the
intake-air-changeover-valve-abnormality-determination-flag XACV is
"1"), the warning notifying the operator of the engine 10 that "the
intake air changeover valve 64 is abnormal" is provided.
Further, when the crank angle of any one of the cylinders coincides
with the predetermined crank angle .theta.g, the CPU 81 starts
executing the routine from step 1000 in FIG. 10, and proceeds to
step 1010. The value of the abnormality-occurrence-flag XEMG is "1"
at the present time, and the CPU 81 therefore makes a "No"
determination at step 1010 to proceed to step 1040.
At step 1040, the CPU 81 obtains the opening degree Accp of the
accelerator pedal based on the output value of the accelerator
opening degree sensor 77, and obtains the engine rotational speed
NE based on the output value of the crank position sensor 75. Then,
the CPU 81 applies the opening degree Accp of the accelerator pedal
at the present time and the engine rotational speed NE at the
present time to the
abnormality-occurring-state-fuel-injection-amount-table MapEmg
(Accp, NE) described above to obtain the fuel injection amount
Q.
Subsequently, the CPU 81 proceeds to step 1030 at which the CPU 81
provides to the injector 22 disposed for the fuel injection
cylinder the instruction to inject the fuel whose amount is the
fuel injection amount Q from the injector 22. That is, at this
time, the fuel whose amount is the fuel injection amount Q is
supplied to the fuel injection cylinder. The CPU 81 thereafter
proceeds to step 1095 at which the CPU 81 ends the present routine
tentatively.
In this manner, when the intake air changeover valve 64 is
abnormal, the first apparatus notifies the operator of the engine
10 that "the intake air changeover valve 64 is abnormal" and
performs the emergency operation.
As described above, the first apparatus provides the instruction to
change the opening degree Oecv of the exhaust gas changeover valve
66 to exhaust gas changeover valve actuator 66a, when the
abnormality determining condition is satisfied. The first apparatus
obtains the supercharging pressure Pim (the referential
supercharging pressure Pim0) at the timing "before" the instruction
is provided, and obtains the supercharging pressure Pim (the
supercharging-pressure-for-a-determination Pim1) at the timing
"after" the instruction is provided. Thereafter, the first
apparatus determines that "the exhaust gas changeover valve 66 is
abnormal" when the absolute value of the difference between the
referential supercharging pressure Pim0 and the
supercharging-pressure-for-a-determination Pim1 is smaller than the
predetermined value (the threshold supercharging pressure Pimth).
On the other hand, in the case where the absolute value of the
difference between the referential supercharging pressure Pim0 and
the supercharging-pressure-for-a-determination Pim1 is larger than
the predetermined value (i.e., the exhaust gas changeover valve 66
operates normally), the first apparatus determines that "the intake
air changeover valve 64 is abnormal" if the
supercharging-pressure-for-a-determination Pim1 is larger than or
equal to the referential supercharging pressure Pim0 when the
instruction to increase the opening degree Oecv of the exhaust gas
changeover valve 66 is provided to the exhaust gas changeover valve
actuator 66a. Further, in the case where the absolute value of the
difference between the referential supercharging pressure Pim0 and
the supercharging-pressure-for-a-determination Pim1 is larger than
the predetermined value, the first apparatus determines that "the
intake air changeover valve 64 is abnormal", if the
supercharging-pressure-for-a-determination Pim1 is smaller than or
equal to the referential supercharging pressure Pim0 when the
instruction to decrease the opening degree Oecv of the exhaust gas
changeover valve 66 is provided to the exhaust gas changeover valve
actuator 66a. Furthermore, when the first apparatus determines that
the intake air changeover valve 64 or the exhaust gas changeover
valve 66 is abnormal, the first apparatus notifies the operator of
the engine accordingly and performs the emergency operation.
That is, the first apparatus is applied to the internal combustion
engine 10 which has:
a first supercharger 61 comprising, a first turbine 61b disposed in
an exhaust gas passage 42 of the engine 10, and a first compressor
61a disposed in an intake air passage 32 of the engine 10 and
driven by the first turbine 61b which is driven by an exhaust gas
flowing in the exhaust gas passage 42;
a second supercharger 62 comprising, a second turbine 62b disposed
in the exhaust gas passage 42 at a downstream side of the first
turbine 61b, and a second compressor 62a disposed in the intake air
passage 32 at an upstream side of the first compressor 61a and
driven by the second turbine 62b which is driven by the exhaust
gas;
a first passage section (the
high-pressure-turbine-bypass-passage-section) 65 whose one end is
connected to the exhaust gas passage 42 at an upstream side of the
first turbine 61b and whose the other end is connected to the
exhaust gas passage 42 between the first turbine 61b and the second
turbine 62b;
a first control valve (the exhaust gas changeover valve) 66,
disposed in the first passage section 65, for varying a flow
passage area of the first passage section 65 depending on an
opening degree of the first control valve 66;
a second passage section (the
high-pressure-compressor-bypass-passage-section) 63 whose one end
is connected to the intake air passage 32 between the first
compressor 61a and the second compressor 62a and whose the other
end is connected to the intake air passage 32 at a downstream side
of the first compressor 61a; and
a second control valve (the intake air changeover valve) 64,
disposed in the second passage section 63, for varying a flow
passage area of the second passage section 63 depending on an
opening degree of the second control valve 64,
and
the engine 10 is configured in such a manner that the first control
valve 66 and the second control valve 64 are operated in such a
manner that at least the first compressor 61a compresses an air
introduced into the first compressor 61a and discharge the
compressed air, when the engine 10 is operated in a predetermined
operating area.
Further, the first apparatus is configured so as to comprise;
supercharging-pressure-corresponding-value-obtaining-means (step
815 and step 825 in FIG. 8) for obtaining a
supercharging-pressure-corresponding-value (the supercharging
pressure Pim, in the present example) which becomes larger as a
pressure of an air in the intake air passage 32 at the downstream
side of the first compressor 61a becomes larger; and
control valve abnormality determination means (refer to the routine
in FIG. 8) for:
obtaining, as a first value, the obtained
supercharging-pressure-corresponding-value (supercharging pressure
Pim), during a period in which an abnormality determining condition
including at least a condition that the engine 10 is operated in
the predetermined area is satisfied (the period in which a "Yes"
determination is made in step 805 in FIG. 8);
operating the first control valve 66, at a first timing after the
timing at which the first value Pim0 is obtained, in such a manner
that the opening degree of the first control valve 66 coincides
with a second opening degree (the fully-opened-opening-degree, in
the present example) different from a first opening degree which is
an opening degree of the first control valve 66 at a timing when
the first value Pim0 is obtained;
obtaining, as a second value Pim1, the obtained
supercharging-pressure-corresponding-value (supercharging pressure
Pim) at a second timing at which a predetermined time has elapsed
from the first timing;
and
determining that the second control valve 64 is abnormal, if the
second opening degree (the fully-opened-opening-degree) is larger
than the first opening degree and the second value Pim1 is larger
than the first value Pim0, or if the second opening degree is
smaller than the first opening degree and the second value Pim1 is
smaller than the first value Pim0.
As described above, the control apparatus of the present invention
can determine whether or not the second control valve (intake air
changeover valve) 64 is abnormal, based on the change in the
supercharging pressure Pim when (between before and after) the
opening degree of the first control valve (exhaust gas changeover
valve 66) is changed.
Further, in the first apparatus,
the supercharging-pressure-corresponding-value-obtaining-means
(step 815 and step 825 in FIG. 8) is configured so as to obtain "a
supercharging pressure Pim" which is a pressure of an air in the
intake air passage 32 at the downstream side of the first
compressor 61a as the supercharging-pressure-corresponding-value
(supercharging pressure Pim).
Further, in the first apparatus,
the control valve abnormality determination means (refer to the
routine in FIG. 8) is configured so as to determine that the first
control valve 66 is abnormal, if an absolute value of a difference
between the second value Pim1 and the first value Pim0 is smaller
than a first control valve-abnormality-determining-threshold-value
Pimth (if a "No" determination is made in step 830 in FIG. 8).
Further, in the first apparatus,
the control valve abnormality determination means (refer to the
routine in FIG. 8) is configured so as to infer that the second
control valve 64 is normal, if the control valve abnormality
determination means determines that the first control valve 66 is
abnormal (i.e., it sets the value of the
exhaust-gas-changeover-valve-abnormality-determination-flag XECV at
"1" at step 860 in FIG. 8, and simultaneously sets the value of the
intake-air-changeover-valve-abnormality-determination-flag XACV at
"0" at step 865).
Further, in the first apparatus,
the first control valve 66 includes a first control valve driving
means (exhaust gas changeover valve actuator 66a) for varying the
opening degree of the first control valve 66 to change the flow
passage area of the first passage section 65 in response to an
instruction signal, and
the control valve abnormality determination means (refer to the
routine of FIG. 8) is configured so as to change the opening degree
of the first control valve 66 by sending the instruction signal to
the first control valve driving means (refer to step 820 in FIG.
8).
Further, in the first apparatus,
the abnormality determining condition is a condition that is
satisfied at least when the engine 10 is operated in a deceleration
state in which a torque required for the engine 10 is smaller than
or equal to a predetermined torque (refer to the Condition 3
described above).
In the meantime, in the internal combustion engine to which the
apparatus for determining an abnormality of a control valve of the
present invention is applied, an inner diameter of the
low-pressure-turbine-bypass-passage-section (bypass pipe) 67 is
"around a diameter which allows only a part of the exhaust gas
discharged from the combustion chambers CC to pass through the
low-pressure-turbine-bypass-passage-section 67, when the
abnormality determining condition is satisfied, and even when the
exhaust gas bypass valve 68 is fully opened. In other words, even
if the exhaust gas bypass valve 68 is fully opened, a part of the
exhaust gas is introduced into the low pressure turbine 62b.
Accordingly, the exhaust gas whose amount is larger than zero is
flowed into the low pressure turbine 62b regardless of the opening
degree of the exhaust gas bypass valve 68. It is therefore possible
for the apparatus for determining an abnormality of a control valve
of the present invention to determine whether or not the intake air
changeover valve 64 and/or the exhaust gas changeover valve 66 is
abnormal, regardless of whether the exhaust gas bypass valve 68 is
normal or abnormal.
The present invention is not limited to the above embodiment, but
may be modified as appropriate without departing from the scope of
the invention.
For example, in the embodiment described above, "the supercharging
pressure" which is the pressure of the air in the intake air
passage at the downstream side of the first compressor is obtained
as the supercharging-pressure-corresponding-value. However, the
apparatus for determining an abnormality of a control valve of the
present invention may be configured so as to obtain, as the
supercharging-pressure-corresponding-value (i.e., a value which
becomes larger as the supercharging pressure which is the pressure
of the air in the intake air passage at the downstream side of the
high pressure compressor 61a serving as the first compressor
becomes larger), "an amount of a new air (a new air amount)" which
is the amount of the air introduced into the engine. In addition,
the supercharging pressure obtained as the
supercharging-pressure-corresponding-value may be a pressure in the
intake air passage between the intercooler 34 and the throttle
valve 33.
Further, in the control valve abnormality determination means of
the present invention, the second control valve 64 may be
configured so as to be operated in such a manner that the second
control valve 64 shuts (completely closes) the second passage
section 63 when the engine 10 is being operated in the
predetermined operating area.
In addition, in the control valve abnormality determination means
of the present invention, as shown in FIG. 11, the intake air
changeover valve 64 serving as the second control vale may be
configured in such a manner that
the intake air changeover valve 64 comprises a valving element 64b,
a valve seat portion 64c against which the valving element 64b
rests, and biasing means (spring) 64d for biasing the valving
element 64b toward the valve seat portion 64c.
The control valve is configured,
in such a manner that the valving element 64b is moved to a first
position at which the valving element 64b rests against the valve
seat portion 64c by an biasing force generated by the biasing means
64d so as to close the second passage section 63 when a pressure of
an air in the second passage section 63 at an upstream side of the
second control valve 64 is not larger than a pressure of an air in
the second passage section 63 at an downstream side of the second
control valve 64 by a predetermined pressure or more, and
in such a manner that the valving element 64b is moved to a second
position different from the first position against the biasing
force generated by the biasing means 64d so as to increase the flow
passage area of the second passage section 63 when the pressure of
the air in the second passage section 63 at the upstream side of
the second control valve 64 is larger than the pressure of the air
in the second passage section 63 at the downstream side of the
second control valve 64 by the predetermined pressure or more.
That is, this second control valve may be a valve operated
independently from an instruction signal generated by the electric
control apparatus 80.
Further, in the embodiment described above, the determination as to
whether or not the intake air changeover valve 64 is abnormal is
made (step 840, step 845, and step 855 in FIG. 8), after the
determination as to whether or not the exhaust gas changeover valve
66 is abnormal is made (i.e., after the "Yes" determination is made
at step 830 in FIG. 8). However, the apparatus for determining an
abnormality of a control valve of the present invention may be
configured so as to determine "whether or not the intake air
changeover valve 64 is abnormal only". More specifically, the
apparatus for determining an abnormality of a control valve of the
present invention may be configured so as to repeatedly execute "a
routine in which step 830, step 860, and step 865 in the
abnormality determination routine shown in FIG. 8 are deleted"
every elapse of a predetermined time period.
Furthermore, in step 820 in the embodiment described above, when
the first opening degree Oecv1 is always sufficiently small (i.e.,
the abnormality determining condition in step 805 includes a
condition which is satisfied when the engine is being operated in a
state where the first opening degree Oecv1 is sufficiently small),
the opening degree Oecv of the exhaust gas changeover valve 66 may
be changed at step 820 in such a manner that the opening degree
Oecv2 is always larger than "the first opening degree Oecv1 which
is the present opening degree (e.g., the second opening degree
Oecv2 is set at the fully-open-opening-degree)". In this case, step
840 and step 845 may be omitted.
Similarly, in step 820 in the embodiment described above, when the
first opening degree Oecv1 is always sufficiently large (i.e., the
abnormality determining condition in step 805 includes a condition
which is satisfied when the engine is being operated in a state
where the first opening degree Oecv1 is sufficiently large), the
opening degree Oecv of the exhaust gas changeover valve 66 may be
changed at step 820 in such a manner that the opening degree Oecv2
is always smaller than "the first opening degree Oecv1 which is the
present opening degree (e.g., the second opening degree Oecv2 is
set at the fully-close degree)". In this case, step 840 and step
855 may be omitted.
Further, in the embodiment described above, the opening degree of
the throttle valve 33 is set at the fully-open-opening-degree (step
810 in FIG. 8) before the opening degree of the first control valve
66 is set at the fully-open-opening-degree (step 820 in FIG. 8).
However, in the apparatus for determining an abnormality of a
control valve of the present invention, the opening degree of the
throttle valve 33 is not necessarily required to be set at the
fully-open-opening-degree, before the opening degree of the first
control valve 66 is changed.
Further, in the embodiment described above, the exhaust gas
changeover valve opening degree sensor 76 is provided to the engine
10. However, the exhaust gas changeover valve opening degree sensor
76 is just a practical example for obtaining the opening degree
Oecv which is shown in the time-line charts of FIG. 4, FIG. 6, and
FIG. 7. That is, the internal combustion engine to which the
apparatus for determining an abnormality of a control valve of the
present invention is applied does not necessarily comprise the
exhaust gas changeover valve opening degree sensor 76.
Further, in the embodiment described above, a determination as to
whether or not the exhaust gas bypass valve 68 is abnormal is not
made. However, the apparatus for determining an abnormality of a
control valve of the present invention may be configured so as to
determine whether or not the exhaust gas bypass valve 68 is
abnormal. More specifically, for example, the apparatus may
provide, to the exhaust gas bypass valve actuator 68a, an
instruction to change the opening degree of the exhaust gas bypass
valve 68 to a certain opening degree different from a current
opening degree of the exhaust gas bypass valve 68, when the engine
10 is being operated in a predetermined operating condition.
Subsequently, the apparatus may obtain a change in the
supercharging pressure Pim when (between before and after) the
instruction is provided. Thereafter, the apparatus can determine
that the exhaust gas bypass valve 68a is abnormal when the change
in the supercharging pressure Pim is smaller than a predetermined
value.
* * * * *